Stuttering issue above 2500 RPM on 06 TJ

[Mermaid25]

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?

 

[TJ Jim]

No codes? I’d suspect fuel delivery issue. What is the fuel pressure? Should be close to 50psi. I bought bad gas one day, the gas delivery truck pumped his diesel treatment into the gas pumps.

 

[JKP]

1. If you have any codes, you're in limp mode.

2. Check the fuel pressure at idle and while blipping the throttle. What brand is the new fuel pump? Many of the cheap aftermarket ones are junk.

3. Your coil may be weak. It's a little tougher to pin down on the coil rails as they have 3 coils. On the old style single coil systems, the engine will just shut off under load/high RPM. With the 3 coil, you may have one or two coils that are weak but it's still running on the other coil(s).

 

[Mermaid25]

No codes? I’d suspect fuel delivery issue. What is the fuel pressure? Should be close to 50psi. I bought bad gas one day, the gas delivery truck pumped his diesel treatment into the gas pumps.

These were the codes: P0032, P0344, P0037, P0052, P0058. Again, she has 4 brand new (within 2 yrs Mopar) O2 sensors … so I highly doubt it’s those; new CPS, new PCM & new fuel pump (idk what kinda fuel pump bc Firestone put it in). Idk what the fuel pressure is at idle but it doesn’t idle hard or have any noticeable acceleration issues in any gear or from stop … only once it hits that dang 2500 sweet spot

 

[JKP]

It's in limp mode, which limits RPM to approx 2500.

The P0344 code is the cam sensor, and on an 06 can also indicate problems with the OPDA that the cam sensor is in.

And those O2 codes are usually a sign of a bad PCM. Did you get a wranglerfix PCM?

 

[Mermaid25]

No codes? I’d suspect fuel delivery issue. What is the fuel pressure? Should be close to 50psi. I bought bad gas one day, the gas delivery truck pumped his diesel treatment into the gas pumps.

These were the codes: P0032, P0344, P0037, P0052, P0058. Again, she has 4 brand new Mopar O2 sensors which I put in myself about 2 yrs ago… brand new CPS, PCM (built by Wranglerfix), fuel pump (idk what brand bc Firestone put it in and I’d have to check or drop the tank). Idk what the fuel pressure is at idle but she doesn’t idle hard or have acceleration issues at any gear or from a stop…. just that dang RPM issue once I hit that sweet spot of 2500. MPG seems pretty normal (no significant loss in fuel consumption… just normal fluctuations depending on AC usage or if I have doors off etc).

 

[Stockli]

Have you checked the map sensor?

 

[Mermaid25]

It's in limp mode, which limits RPM to approx 2500.

The P0344 code is the cam sensor, and on an 06 can also indicate problems with the OPDA that the cam sensor is in.

And those O2 codes are usually a sign of a bad PCM. Did you get a wranglerfix PCM?

Yes… if you read further or my original post, put in a new CPS & a new PCM (by wranglerfix)… only thing I have put in is a new OPDA (haven’t checked if it’s a Crown bc I know that the OEM redesign OPDA for ‘06 is also faulty)… thanks for the input.

 

[JKP]

I would talk to Mark at wranglerfix about the O2 codes and check the O2 wiring.

Check the cam sensor wiring around the dipstick.

In general, the P0344 code is for intermittent cam signal, which usually means a bad cam sensor if the wiring is good. Some aftermarket cam sensors are problematic and will throw the code.

If the OPDA is worn to the point the tone wheel is wobbling, this can also throw off the cam sensor signal.

But, you need to pull the OEM OPDA and check for binding and gear wear anyway.

If you reset the codes, you will get out of limp mode until it throws the cam sensor code again.

 

[Mermaid25]

I would talk to Mark at wranglerfix about the O2 codes and check the O2 wiring.

Check the cam sensor wiring around the dipstick.

In general, the P0344 code is for intermittent cam signal, which usually means a bad cam sensor if the wiring is good. Some aftermarket cam sensors are problematic and will throw the code.

If the OPDA is worn to the point the tone wheel is wobbling, this can also throw off the cam sensor signal.

But, you need to pull the OEM OPDA and check for binding and gear wear anyway.

If you reset the codes, you will get out of limp mode until it throws the cam sensor code again.

lol… yes I will talk to Mark about the O2 code bc I just bought a new PCM fr him which was installed last Thursday but it didn’t fix the RPM issue. Again, prior to me getting a PCM fr Mark, my mechanic replaced the cam sensor, checked ths wiring bc a ground was faulty or something. Only thing I haven’t checked or changed pretty much at this point is the OPDA… Mark did tell me that if it’s still the original OEM OPDA, then to go ahead and change it to a Crown OPDA (even if OEM one isn’t bad bc apparently the redesigned OPDA for the ‘06 is faulty). I’m building another checklist for my mechanic to check off again from these inputs. Thanks!

 

[Apparition]

How are your catalytic converters?

 

[Mermaid25]

How are your catalytic converters?

Idk but I seriously doubt it’s ther bc code for a bad catalytic converter has never come up … always some kinda O2 code or CPS related code. Symptoms too would make it appear as if it’s a fuel delivery system or electrical/sensor issue…. But then again, the symptoms that it’s mechanical such as a bad fuel pump don’t all match as runs & feels absolutely normal other than when it reaches 2500 RPM … and besides (as I’ve mentioned several times in this thread) it has a brand new fuel pump that was installed in 2023. It’s a straight 6 manual 4.0 Rubicon and it’s obviously in limp mode (or limp home mode) when it reaches that 2500 threshold.

I’m fixing to just put in a Crown OPDA bc that’s about the only thing I haven’t replaced. I can do most any repair work myself mechanically (and I am definitely not a mechanic… just a garage girl who loves cars ) but anything electrical isn’t definitely outta my wheelhouse so I’ve been taking it to my mechanic of 20 yrs but they are just as frustrated and stumped at this point so I jumped onto this forum.

Btw… for anyone else reading this, couple of questions:

1) Is it bad for me to be driving my baby around as long as I’m keeping it under 2200 RPMs (because as I said, it runs and feels absolutely normal otherwise)

2) the CPS has been changed but I’ve been reading a lot of threats saying that unless it’s a Mopar CPS, then it may continue to throw the P0344 code.

I am so confused and pulling my hair out at this point that I’m afraid I’ll be bald soon

 

[tr21triton]

How are your catalytic converters?

BINGO, sounds like how my '05 acted when the cats honeycomb dislodged but I had no codes.

 

[Mermaid25]

Idk but I seriously doubt it’s ther bc code for a bad catalytic converter has never come up … always some kinda O2 code or CPS related code. Symptoms too would make it appear as if it’s a fuel delivery system or electrical/sensor issue…. But then again, the symptoms that it’s mechanical such as a bad fuel pump don’t all match as runs & feels absolutely normal other than when it reaches 2500 RPM … and besides (as I’ve mentioned several times in this thread) it has a brand new fuel pump that was installed in 2023. It’s a straight 6 manual 4.0 Rubicon and it’s obviously in limp mode (or limp home mode) when it reaches that 2500 threshold.

I’m fixing to just put in a Crown OPDA bc that’s about the only thing I haven’t replaced. I can do most any repair work myself mechanically (and I am definitely not a mechanic… just a garage girl who loves cars ) but anything electrical isn’t definitely outta my wheelhouse so I’ve been taking it to my mechanic of 20 yrs but they are just as frustrated and stumped at this point so I jumped onto this forum.

Btw… for anyone else reading this, couple of questions:

1) Is it bad for me to be driving my baby around as long as I’m keeping it under 2200 RPMs (because as I said, it runs and feels absolutely normal otherwise)

2) the CPS has been changed but I’ve been reading a lot of threats saying that unless it’s a Mopar CPS, then it may continue to throw the P0344 code.

I am so confused and pulling my hair out at this point that I’m afraid I’ll be bald soon

Omg … pls disregard my typos above as it’s only 8:30a here and I haven’t eaten breakfast and my brain is on overload with having to try and diagnose and fix this mystery issue. And aside from tearing my TJ completely apart and checking each system AGAIN physically (which I do not have the time for) …from fuel pump, O2 sensors, wiring etc that have all already been replaced, idk what to do. There’s really not much to this car as it’s completely manual so…. Arrrrrgh!

 

[tr21triton]

How many miles on your Jeep and how about spark plugs ?

 

[Mermaid25]

How many miles on your Jeep and how about spark plugs ?

lol… oh boy … not sure exactly but it is hitting around the 250k mark I believe (if it’s not already above that) but I don’t driver her hard and I do regular maintenance as far as oil & oil filter about every 3 months. I asked about the spark plugs bc i myself have never changed them since I bought her almost 3 yrs ago (one owner before me) … however, everyone and my mechanics that I’ve asked if it could possibly be a spark plug or piston/valve/cylinder related issue all say no

 

[tr21triton]

lol… oh boy … not sure exactly but it is hitting around the 250k mark I believe (if it’s not already above that) but I don’t driver her hard and I do regular maintenance as far as oil & oil filter about every 3 months. I asked about the spark plugs bc i myself have never changed them since I bought her almost 3 yrs ago (one owner before me) … however, everyone and my mechanics that I’ve asked if it could possibly be a spark plug or piston/valve/cylinder related issue all say no

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.

 

[Apparition]

Idk but I seriously doubt it’s ther bc code for a bad catalytic converter has never come up … always some kinda O2 code or CPS related code. Symptoms too would make it appear as if it’s a fuel delivery system or electrical/sensor issue…. But then again, the symptoms that it’s mechanical such as a bad fuel pump don’t all match as runs & feels absolutely normal other than when it reaches 2500 RPM … and besides (as I’ve mentioned several times in this thread) it has a brand new fuel pump that was installed in 2023. It’s a straight 6 manual 4.0 Rubicon and it’s obviously in limp mode (or limp home mode) when it reaches that 2500 threshold.

I’m fixing to just put in a Crown OPDA bc that’s about the only thing I haven’t replaced. I can do most any repair work myself mechanically (and I am definitely not a mechanic… just a garage girl who loves cars ) but anything electrical isn’t definitely outta my wheelhouse so I’ve been taking it to my mechanic of 20 yrs but they are just as frustrated and stumped at this point so I jumped onto this forum.

Btw… for anyone else reading this, couple of questions:

1) Is it bad for me to be driving my baby around as long as I’m keeping it under 2200 RPMs (because as I said, it runs and feels absolutely normal otherwise)

2) the CPS has been changed but I’ve been reading a lot of threats saying that unless it’s a Mopar CPS, then it may continue to throw the P0344 code.

I am so confused and pulling my hair out at this point that I’m afraid I’ll be bald soon

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

 

[Apparition]

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.

When my cats failed, I changed my plugs at an O'Reilly's to confirm it wasn't them. Then after the remainder of my 8 hour drive, that I couldn't exceed 55 mph, and a nights sleep, I figured out it was the cats.

 

[Link]

Another recommendation to check the cats. You can pull the pre cat O2 sensor and check them with a back pressure gauge. Any muffler shop should be able to do it or you could buy a gauge off Amazon and do it yourself.