Stuttering issue above 2500 RPM on 06 TJ

[AaronPaul]

Hi everyone… my first post here and I know my issue is common but I cannot seem to find a solution for my ‘06 TJ stuttering around 2500 RPMs … can’t get past that threshold. My mechanics (whom I love and have taken all of my cars to for at least 20 yrs) are at a total loss as to what’s causing it. Quick rundown … started after I got full tank of gas one day … so we thought bad gas… did 2 gas treatments, put high octane fuel… didn’t fix the problem. Here’s a list of all that’s been done to try to find the cause due to codes pulled… replaced CPS… then put replace PCM … not fixed. Found out that ‘05 & ‘06 OEM PCM faulty by design… got new PCM from Wranglerfix (recommended by a lot of TJ forums advice)… still didn’t fix issue. Since I bought the TJ about 4 yrs ago I’ve replace all 4 O2 sensors, it’s got a brand new fuel pump, air filter has been replaced, new clutch kit bc throwout bearings went out, replaced a radiator hose & replaced AC compressor/blower. So she’s practically new! LOL. HOWEVER… we can’t seem to find what’s causing this RPM issue above 2500… Jeep acts normally otherwise in any gear (manual transmission) as long as it doesn’t go above (or near) 2500 RPMs!
Btw… I change her oil & filter religiously myself about every 3000 - 5000 miles … oh and I’ve changed her brakes pads, calipers & rotors… and she has new shoes (aka.. tires). Lastly (sorry for the long post but I want to give as much info)… my cruise control was acting up prior to my RPM problem … I was on cruise control when it suddenly shut off and then it stuttered for the first time … prior to that, the CC never had issues except the CC started to turn completely off (disengage) when I pressed the coast or resume button (right side on steering wheel)… any help on this RPM issue?

• Oxygen Sensors – You’ve replaced the O2 sensors before, but it’s worth checking them again. Particularly the upstream sensors, as they play a major role in regulating fuel and air mixture, which can affect performance at higher RPMs. If these sensors are giving faulty readings, they can cause hesitation or stuttering as the engine tries to adjust.
• Crankshaft Position Sensor (CPS) – You've replaced the CPS already, but it's one of the key parts that could cause intermittent stuttering. I know there can be problems with aftermarket CPS parts that don’t meet OEM specs, which can lead to erratic engine behavior. If you suspect that the new CPS is malfunctioning or not calibrated properly, it's worth revisiting this.
• Vacuum Leaks – Although you've done some checks, vacuum leaks are often hard to track down without a detailed method like using propane. A small vacuum leak can significantly impact air/fuel mixture and performance, especially at higher RPMs, and doesn’t always trigger a code. Carb cleaner will work too.
• Throttle Position Sensor (TPS) – Since the throttle position sensor controls air/fuel mixture at different throttle positions, any irregular readings, especially in the 2000-2500 RPM range, could cause stuttering. Even though you've replaced this sensor, it’s worth checking the connection and recalibration.

 

[Mermaid25]

so he says a engine stutter couldn't be a spark plug ? I'd find a new mechanic ! that should be the 1st thing you check for a engine miss or stuttering ! Pull your plugs and get a look at them.

Hahahaha… I get that but I do trust my mechanics… they’re like family and usually the only ones I’ve taken and trust to work on any of my cars (if I can’t or don’t want to fix something myself)… been working with them for 20 yrs or so. However, tbh, they really don’t work on Jeeps (more foreign car work and definitely AC/radiator specialists) … and other people/mechanics etc have poo-pooed the spark plugs as possible culprits (including my son who is very much mechanically inclined and works on his Jeep, cars & motorcycles himself often vs taking to mechanics). Anyhooooo… I’m taking my TJ to a Jeep garage today as well as taking it down to Mark @Wranglerfix probably tomorrow or Wednesday to have him test the PCM that I bought fr him as well as my old PCM to see if it they can help me finally figure this out. I’ve been trying to solve this for a month now and I’m just tired … of fixing & replacing parts bc of codes pulled yet no solution as of yet and between paying for Lyfts to or from garage, labor & parts I’m deep into this “fix” almost around $2k… labor & diagnostic costs alone are killing me … and like I said, I’d do most of these things myself (like the cps) and possibly now a new OPDA (which I can do with the help of son bc I’ll need him to make sure it’s rotated to top dead center) since that part is probably only $100 or so but the labor for someone else to do it will end up doubling…. maybe even tripling that cost… but I don’t have the time necessarily to do it myself rn as I do have a company to run

And yes… regardless I’m just about to throw up my hands and just replace all the spark plugs too at this point just so that I known they’re new … even tho the car starts up just fine with not hesitation and doesn’t otherwise show any stuttering or misfires at lower gears or ANY gears as long as I’m under 2500 rpm

 

[Mermaid25]

I never received any codes for my cats when they failed. I hit a random misfire whenever I would exceed 55 mph.

But this is not a speed problem… definitely only an RPM problem bc I can run it at 55mph … maybe even up to 60… but once it opens up and pushes above that 2500 threshold, then that’s when it goes into limp mode symptoms (stuttering and can’t get up to or maintain speed of 60mph)

 

[Mermaid25]

• Oxygen Sensors – You’ve replaced the O2 sensors before, but it’s worth checking them again. Particularly the upstream sensors, as they play a major role in regulating fuel and air mixture, which can affect performance at higher RPMs. If these sensors are giving faulty readings, they can cause hesitation or stuttering as the engine tries to adjust.
• Crankshaft Position Sensor (CPS) – You've replaced the CPS already, but it's one of the key parts that could cause intermittent stuttering. I know there can be problems with aftermarket CPS parts that don’t meet OEM specs, which can lead to erratic engine behavior. If you suspect that the new CPS is malfunctioning or not calibrated properly, it's worth revisiting this.
• Vacuum Leaks – Although you've done some checks, vacuum leaks are often hard to track down without a detailed method like using propane. A small vacuum leak can significantly impact air/fuel mixture and performance, especially at higher RPMs, and doesn’t always trigger a code. Carb cleaner will work too.
• Throttle Position Sensor (TPS) – Since the throttle position sensor controls air/fuel mixture at different throttle positions, any irregular readings, especially in the 2000-2500 RPM range, could cause stuttering. Even though you've replaced this sensor, it’s worth checking the connection and recalibration.

Thanks for this … yes… I think I mentioned somewhere in this now getting to be long thread… that apart from breaking down and checking and RECHECKING all the systems manually, I’ve done everything and anything possible that could be wrong to throw off all those codes. The new CPS is
Mopar… the O2 sensors (all 4) are also Mopar and they’ve been in my Jeep now at least 2 yrs so I can’t imagine them being bad now but idk. I asked about it possibly being a vacuum leak somewhere and they say highly unlikely (but I don’t think they did a vacuum check) … I did think about it being related to TPS. However, my gut is actually telling me it probably the OPDA

At this point, this TJ is practically brand new with the exception of the engine . If I didn’t love this particular year and model Jeep so much, I would’ve probably unloaded her already… I mean let’s face it… she’s not the most practical car nowadays especially as my daily driver

 

[Apparition]

But this is not a speed problem… definitely only an RPM problem bc I can run it at 55mph … maybe even up to 60… but once it opens up and pushes above that 2500 threshold, then that’s when it goes into limp mode symptoms (stuttering and can’t get up to or maintain speed of 60mph)

It wasn't actually a speed issue for me either it was a load issue. It just correlated to 55 mph. As soon as the load increased too much, limp mode. Reset it and start over.

 

[tr21triton]

Hahahaha… I get that but I do trust my mechanics… they’re like family and usually the only ones I’ve taken and trust to work on any of my cars (if I can’t or don’t want to fix something myself)… been working with them for 20 yrs or so. However, tbh, they really don’t work on Jeeps (more foreign car work and definitely AC/radiator specialists) … and other people/mechanics etc have poo-pooed the spark plugs as possible culprits (including my son who is very much mechanically inclined and works on his Jeep, cars & motorcycles himself often vs taking to mechanics). Anyhooooo… I’m taking my TJ to a Jeep garage today as well as taking it down to Mark @Wranglerfix probably tomorrow or Wednesday to have him test the PCM that I bought fr him as well as my old PCM to see if it they can help me finally figure this out. I’ve been trying to solve this for a month now and I’m just tired … of fixing & replacing parts bc of codes pulled yet no solution as of yet and between paying for Lyfts to or from garage, labor & parts I’m deep into this “fix” almost around $2k… labor & diagnostic costs alone are killing me … and like I said, I’d do most of these things myself (like the cps) and possibly now a new OPDA (which I can do with the help of son bc I’ll need him to make sure it’s rotated to top dead center) since that part is probably only $100 or so but the labor for someone else to do it will end up doubling…. maybe even tripling that cost… but I don’t have the time necessarily to do it myself rn as I do have a company to run

And yes… regardless I’m just about to throw up my hands and just replace all the spark plugs too at this point just so that I known they’re new … even tho the car starts up just fine with not hesitation and doesn’t otherwise show any stuttering or misfires at lower gears or ANY gears as long as I’m under 2500 rpm

I suggest AUTOLITE XP985 , they cost a little more but they'll last over 100k miles.

 

[Mermaid25]

It wasn't actually a speed issue for me either it was a load issue. It just correlated to 55 mph. As soon as the load increased too much, limp mode. Reset it and start over.

I suggest AUTOLITE XP985 , they cost a little more but they'll last over 100k miles.

Thanks! Okey dokey

 

[Harold&Cat]

We didn't get any codes when our Catalytic converters stopped up . Didn't have any power on the highway . Installed new Cats and it ran fine . I would definitely check the Cats with the high mileage on your Jeep .

 

[tr21triton]

You say you like to do most of the work on it yourself. If this isn't your daily driver I'd stop taking it to shops and troubleshoot it yourself, might take some time but will save you LOTS of money (WHICH WE WILL HELP YOU SPEND ON YOUR JEEP AFTER IT'S FIXED) . The members on this forum are great and if they can't help you figure it out and get it fixed IT'S READY FOR THE SCRAP YARD !

 

[Mermaid25]

We didn't get any codes when our Catalytic converters stopped up . Didn't have any power on the highway . Installed new Cats and it ran fine . I would definitely check the Cats with the high mileage on your Jeep .

Ugh… yet another not-so-cheap fix if it is

Let me see what happens after I take it to a JEEP garage today and after I see what Mark comes up with when I bring it down to him to test the new PCM and old PCM and see what they say before I decide on replacing anything more on KEALA (yes that’s her name … fyi, it’s Hawaiian for “the Path” … and yes… yes I sure did name my TJ). Thanks everybody for the inputs … really appreciate it … but my brain hurts from these shenanigans with my Jeep . I’ll keep y’all posted!

 

[tr21triton]

Ugh… yet another not-so-cheap fix if it is

Let me see what happens after I take it to a JEEP garage today and after I see what Mark comes up with when I bring it down to him to test the new PCM and old PCM and see what they say before I decide on replacing anything more on KEALA (yes that’s her name … fyi, it’s Hawaiian for “the Path” … and yes… yes I sure did name my TJ). Thanks everybody for the inputs … really appreciate it … but my brain hurts from these shenanigans with my Jeep . I’ll keep y’all posted!

AWE SHIT, Mark will figure out whats wrong with it, you should of said you were taking it to him ! @Wranglerfix is one of the best and just a great person to deal with

 

[Mermaid25]

AWE SHIT, Mark will figure out whats wrong with it, you should of said you were taking it to him ! @Wranglerfix is one of the best and just a great person to deal with

… guess you didn’t read all of the now never-ending threads . Yes my new PCM is from Mark @Wranglerfix … fr what I hear, he is the man so I had high hopes that his new PCM would FINALLY solve my issue but when it didn’t… well … here we are….

 

[tr21triton]

… guess you didn’t read all of the now never-ending threads . Yes my new PCM is from Mark @Wranglerfix … fr what I hear, he is the man so I had high hopes that his new PCM would FINALLY solve my issue but when it didn’t… well … here we are….

no I saw you had his PCM but didn't see that was who you were taking it to

 

[AaronPaul]

Thanks for this … yes… I think I mentioned somewhere in this now getting to be long thread… that apart from breaking down and checking and RECHECKING all the systems manually, I’ve done everything and anything possible that could be wrong to throw off all those codes. The new CPS is
Mopar… the O2 sensors (all 4) are also Mopar and they’ve been in my Jeep now at least 2 yrs so I can’t imagine them being bad now but idk. I asked about it possibly being a vacuum leak somewhere and they say highly unlikely (but I don’t think they did a vacuum check) … I did think about it being related to TPS. However, my gut is actually telling me it probably the OPDA

At this point, this TJ is practically brand new with the exception of the engine . If I didn’t love this particular year and model Jeep so much, I would’ve probably unloaded her already… I mean let’s face it… she’s not the most practical car nowadays especially as my daily driver

Let me know if I can help any further. I think for the most part you are on the right check, but I would 100% look for vacuum leaks. I mean you might as well at this point lol.
And yes, they may not be the most practical, but we do love em lol

 

[JKP]

But this is not a speed problem… definitely only an RPM problem bc I can run it at 55mph … maybe even up to 60… but once it opens up and pushes above that 2500 threshold, then that’s when it goes into limp mode symptoms (stuttering and can’t get up to or maintain speed of 60mph)

As long as the check engine light is on for P0344, you will never get above 2500.

Plugs are supposed to be changed every 30K if they are not platinum, iridium.

 

[bohuggabee]

Hi everyone… my first post here and I know my issue is common but I cannot seem to find a solution for my ‘06 TJ stuttering around 2500 RPMs … can’t get past that threshold. My mechanics (whom I love and have taken all of my cars to for at least 20 yrs) are at a total loss as to what’s causing it. Quick rundown … started after I got full tank of gas one day … so we thought bad gas… did 2 gas treatments, put high octane fuel… didn’t fix the problem. Here’s a list of all that’s been done to try to find the cause due to codes pulled… replaced CPS… then put replace PCM … not fixed. Found out that ‘05 & ‘06 OEM PCM faulty by design… got new PCM from Wranglerfix (recommended by a lot of TJ forums advice)… still didn’t fix issue. Since I bought the TJ about 4 yrs ago I’ve replace all 4 O2 sensors, it’s got a brand new fuel pump, air filter has been replaced, new clutch kit bc throwout bearings went out, replaced a radiator hose & replaced AC compressor/blower. So she’s practically new! LOL. HOWEVER… we can’t seem to find what’s causing this RPM issue above 2500… Jeep acts normally otherwise in any gear (manual transmission) as long as it doesn’t go above (or near) 2500 RPMs!
Btw… I change her oil & filter religiously myself about every 3000 - 5000 miles … oh and I’ve changed her brakes pads, calipers & rotors… and she has new shoes (aka.. tires). Lastly (sorry for the long post but I want to give as much info)… my cruise control was acting up prior to my RPM problem … I was on cruise control when it suddenly shut off and then it stuttered for the first time … prior to that, the CC never had issues except the CC started to turn completely off (disengage) when I pressed the coast or resume button (right side on steering wheel)… any help on this RPM issue?

This is a common issue. Chasing problems... dont chase problems. If something works, and you replace it, you dont know if what you replaced will fail too. Replace something, if the same issue. Put back on the older part and keep the new stuff for the future. You learned what isnt wrong with the car. Reset computer and try again. If the car wont run over 2500 rpm and its sputtering. Thats fuel mixture or compression issues, or timing. Your fly wheel could even be unbalanced or a bearing failing. The fuel injectors could be clogging. A valve is sticking at temperature. You said you tried octane boosters? Thats a problem too. My engine failed after my father had the bright idea of using octane boost and injector cleaner in my jeep. Pissed me off.

Try this. Its what i did and my jeep isnt perfect still, but it helps. I know it sounds crazy. But use a 20,000 mile oil filter. I use k&m. Then use a high mileage rated oil. Mobil 1 i think too came out with an oil that is proven to restore your engine. I want to try it but . I use the castrol partial synthetic. 10-30 but try 5w-30 for a while. Dont change your filter. Drive it 2,000 miles. Change just the oil. Drive 3,000 miles and see. If that helps. Then you just need to worry about oil pressure. Keep the same filter. Then change it after changing the oil the second time. Reading the oil will teach you wonders about an engine. I went from tar black oil to amber at the same intervals.

Ive been doing it for years now but i dont need to change my oil in my jeep but once a year. The oil is clear and burns off but i add a liter. Change oil. Burn a liter. Change oil and filter.

What this does is. The oil filter is free flowing. It cleans the engine. Instead of cleaning the oil. Metal actually canonizes and buffs itself. Purely clean oil wont replace those minerals you need for the engine to sustain. It removes them and the engine gets off balance and loses compression. Smoother piston rings and smoother metal to metal is what makes an engine smooth.

At one point. One month. I got 42 mpg in a 99 jeep wrangler 4.0... so i think i know what im talking about.