P0300 and P0300 codes

[TimBoteler]

My wife’s 2005 Jeep Wrangler has been having issues. It keeps giving me these codes P0300 Random/ Multiple Cylinder misfire, P0300 Crankshaft Position Sensor A Circuit, P0344 Camshaft Position Sensor A Circuit intermittent Bank 1 or single sensor. I have replaced the cam and crankshaft sensors, timing chain, coil, plugs and computer. Probably not related but also replaces the fuel injectors, fuel pump, and oil pump. I have been leaning towards the camshaft synchronizer next. Getting fed up with it. Any help would be appreciated. Thank you

 

[Chris]

My wife’s 2005 Jeep Wrangler has been having issues. It keeps giving me these codes P0300 Random/ Multiple Cylinder misfire, P0300 Crankshaft Position Sensor A Circuit, P0344 Camshaft Position Sensor A Circuit intermittent Bank 1 or single sensor. I have replaced the cam and crankshaft sensors, timing chain, coil, plugs and computer. Probably not related but also replaces the fuel injectors, fuel pump, and oil pump. I have been leaning towards the camshaft synchronizer next. Getting fed up with it. Any help would be appreciated. Thank you

The P0300 code can be especially tricky since it points to a misfire in multiple cylinders without specifying which one.

For all you know you could have a crack in the cylinder head. I would suggest a leakdown / compression test, and then I would suggest getting ahold of a mechanic who has a scan tool that can read real time data from the engine. These are absolutely priceless tools that can help you to narrow down your issue. If you don't know how to use one, it's worth paying someone who does.

Right now you're just throwing parts at it which is a good way to waste time and money. Again, it could be something you'd never think to check (like the crack in the cylinder head).

Additionally, it might be worth checking the following:

Vacuum Leaks: Sometimes, a vacuum leak can cause random misfires. Check hoses and the intake manifold for any signs of leaks.

Wiring and Connections (can't stress this enough!): Inspect the wiring related to your sensors and ignition system. Loose or corroded connections can lead to intermittent issues.

Ground Connections: Poor ground connections can also lead to erratic sensor readings, which may trigger misfire codes.

 

[JKP]

You have an 05 which has a known bad OPDA design. You need to pull and inspect the OPDA for the shaft seizing and the cam and OPDA gears for wear. Replace with either the Crown or Dorman OPDA.

Not related to this issue, but the 05 PCMs are junk too, so be prepared to replace it when you start getting O2 sensor error, shutting off while driving, gauges dropping out, etc. If you have an AT, expect shifting issues as well.

 

[Moglocker]

You have an 05 which has a known bad OPDA design. You need to pull and inspect the OPDA for the shaft seizing and the cam and OPDA gears for wear. Replace with either the Crown or Dorman OPDA.

Not related to this issue, but the 05 PCMs are junk too, so be prepared to replace it when you start getting O2 sensor error, shutting off while driving, gauges dropping out, etc. If you have an AT, expect shifting issues as well.

Hello mark?

 

[Rcroane]

You said you replaced the computer (PCM)....where did you get it?

 

[TimBoteler]

You have an 05 which has a known bad OPDA design. You need to pull and inspect the OPDA for the shaft seizing and the cam and OPDA gears for wear. Replace with either the Crown or Dorman OPDA.

Not related to this issue, but the 05 PCMs are junk too, so be prepared to replace it when you start getting O2 sensor error, shutting off while driving, gauges dropping out, etc. If you have an AT, expect shifting issues as well.

Thank you that was my next step.

 

[TimBoteler]

You said you replaced the computer (PCM)....where did you get it?

Yes I replaced it twice. I can’t remember where I got it. What would make them go bad?

 

[JKP]

The 05, 06 PCMs are a bad design. Wranglerfix has rehosted it to a more reliable PCM. Don't buy a repaired 05. 06 PCM.

 

[tr21triton]

Yes I replaced it twice. I can’t remember where I got it. What would make them go bad?

Not getting it from @Wranglerfix !

 

[Rcroane]

Yes I replaced it twice. I can’t remember where I got it. What would make them go bad?

Before you throw any more parts at the problem, call Mark at WranglerFix.

 

[Wranglerfix]

Thanks for the tags and good morning from Miami.

The p0300 code is usually never in the pcm. Who’s pcm are you running? Does your current pcm have ridges in the back or is it flat? I can test it for you as a courtesy if you would like to send it into me.

Thanks,

Mark

 

[CleverName]

Had this issue with my 2000 TJ. Replaced the upstream O2's and this solved nothing. Next step was to replace the spark plugs and coil pack. This actually (for now) solved my issue. Driven a couple hundred miles since and no new occurrences.

However, it idles at around 500rpm's and has a bit of a rough idle. Almost like a slight misfire. I know this is just the entry to the can of worms that these problems seem to be caused by, but is that idle too low? and could that be contributing to the rough feel at idle? The idle is inconsistent as well, kinda floats above and below 500.

Thanks.

 

[Rcroane]

Had this issue with my 2000 TJ. Replaced the upstream O2's and this solved nothing. Next step was to replace the spark plugs and coil pack. This actually (for now) solved my issue. Driven a couple hundred miles since and no new occurrences.

However, it idles at around 500rpm's and has a bit of a rough idle. Almost like a slight misfire. I know this is just the entry to the can of worms that these problems seem to be caused by, but is that idle too low? and could that be contributing to the rough feel at idle? The idle is inconsistent as well, kinda floats above and below 500.

Thanks.

Yeah, that's low. Clean your throttle body and see if that helps.