P0172 and P0175

[Twin_Screwed_Cobra]

My car has a misfire code on cylinder #3 and is running too rich on banks 1 and 2. Car idles at about 400-500 RPM and bogs down when driving down the road to the point where I have to pull off because I lose all power. It's really a 50/50 chance as to when it happens, it seems to happen intermittently. I've tried changing the coil pack but the issue still persists. I wouldn't imagine a single spark plug would cause it to run so bad so I'm starting to think maybe it's a fuel injector issue? It smells like straight sulfur behind the car and pops on deceleration. Trying to find the source of the problem sooner than later to try and save money. Any help would be appreciated.

Thanks

 

[Tbone]

I'd change the spark plug first and go from there. If still have the lean codes I'd start looking at o2 sensors and o2 extension harnesses if you used them with your long tubes.

 

[Twin_Screwed_Cobra]

Changed the plug and it got rid of that specific misfire code only for another code to show up, P0136, a start-up misfire under 1000 RPM. It's not bad fuel as I've run 3 or 4 tanks through it. I'm currently trying to get rid of these shitty 02 extensions but for the life of me I can't figure out how to unhook the harness so they'll stretch out more.

 

[Tbone]

Hmm think some people have had issues with the cop wire under the fuse panel under the hood. Take the cover off, then I think its a few torx screws to lift the fuse holder portion off. Look for burnt wire, plastic will be burned also.

Quick and easy check. No use replacing parts if a piece controlling them is messed up.

Also howany miles you have on those plugs, and what brand?

 

[Dino Dino Bambino]

Dirt or oil from the PCV system can foul the throttle body & MAF sensor and cause all sorts of wierd problems so you could try cleaning them. You never know it might just work.

 

[Twin_Screwed_Cobra]

Replaced the crankshaft sensor and that cleared up the rough idle. Still running rich on bank 2 however and I'm way down on power. Did some datalogging and the long term fuel trim is stuck at -20. Probably gonna start pulling injectors on that bank to see if they're stuck.


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[Tbone]

Maybe try switching the o2 sensors from bank to bank. If the rich code follows the sensor to bank 1, you know its a bad sensor. Quick easy check before pulling out injectors.

 

[Twin_Screwed_Cobra]

I actually did that but it stayed rich on that same bank. Come to find out when I was pulling the spark plugs on bank 2 to check for fuel and carbon build up, the plug on cylinder 5 had backed almost the whole way out, it was only held in by a few threads and there was a puddle of fuel down where the coil pack meets the plug. Explains why all of a sudden I thought I had a really bad exhaust leak, instead it was air being pushed through the top of the cylinder... I'm curious as to what made the plug back out. Cars got 73k miles and it's never been touched before.


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[808muscle]

What brand Cops are you running? Stock or aftermarket?

 

[Dino Dino Bambino]

Replaced the crankshaft sensor and that cleared up the rough idle. Still running rich on bank 2 however and I'm way down on power. Did some datalogging and the long term fuel trim is stuck at -20. Probably gonna start pulling injectors on that bank to see if they're stuck.

Did you try what I suggested earlier?

 

[Tbone]

73k miles and it backed out? Thats really odd, most have issues trying to get them out! Replace the plugs and inspect the head threads for damage. Sounds like thats definately the source of your problems. Was a pain to diagnose but hey, still a relatively cheap fix!