Update new alternator installed and no more fluctuating idle it is now gone and no more weird trans shifts or issues at all.
Mine has the same issue randomly. I put in a higher amp battery. Seemed to help ( in Canada )
I'm having the exact same issues with my 2010 300c 5.7I think your whole problem has to do with the P0155 code.
Ok here’s some theory first: Disconnecting the power to the PCM is erasing not only codes, but also the adaptive memory that is learned from the oxygen sensors.
The oxygen sensor needs the heater to maintain a certain temperature to send a proper signal to the PCM regarding fuel mixture.
If the heater doesn’t work, the sensor will cool down and send a higher voltage signal (high voltage = rich and low voltage = lean). So basically it takes the PCM a while to adapt, and a continual high voltage reading will make the PCM try to lean out that bank. After trying to lean that bank it will reach a threshold and set a code. It will keep trying to compensate and eventually make it so lean it starts misfiring. So the P0300 and P0175 are most likely caused by the heater circuit problem.
You have replaced that sensor so you can assume the sensor is good so it’s either a wiring issue or the heater driver in the PCM is bad. You’re going to need to do some circuit checks and I think you’ll find the problem.
I have access to wiring diagrams that I can give you. What year is this car so I can look up the proper diagram?
So what did you do to fix the problem im going through the same thing on my 5.7Ordered a pcm just in case thank you for that website! Now I do have another issue going on my 6.1 when starting it’ll start idle and chop real bad then shutoff. Try and start it it’ll start then die instantly. Pulled fuse 11 for 10 secs then started it then back to normal again like what it is going on !
Just do what i did and get a new PCM and it will fix the problem, but before doing that try the cheaper options first which is Camshaft sensor, crankshaft sensor, check your MAF sensor is clean, make sure your throttle body is clean.So what did you do to fix the problem im going through the same thing on my 5.7
I still havent sorted out my idle / misfire issues due to no one responding to my other posts, so maybe i'll get lucky third time???
Anyways so im going to try this again.....
Idle is rough, car shakes, rpm is at around 600.
This happens on cold starts when the car calms down after starting and does the same when warmed up. rough idle is still there.
When driving, at a random time when i accelerate from a stop sometimes it hesitates and then it wouldn't accelerate further at all, tries to accelerate, bogs / jerks and gives me a random misfire code P0300 and starts misfiring. I also have a Bank 2 / sensor 1 code heater circuit which i cant seem to solve, ive replaced 02 sensor, its still there, i've put in new spark plugs (OEM), coils (OEM, swapped them over also), new intake gaskets, new engine oil, new coolant, new coolant reservoir, throttle body is cleaned out, checked my intake manifold inside and there is a small pool of oil in there. New IAT also. MAF sensor looks dirty (oil) and has some small deposits on the inside of the little tube. Last mechanic who checked the computer, cyclinder 1,3,5,7 are rich and i can smell alot of fuel from driver's side exhaust and passenger side not so much.
A small trick i do is whenever this happens i disconnect the negative terminal and connect it again and it drives fine for like 15 mins to an hour and sometimes randomly. Furthest i've driven without random misfire was 2 days. It happened again to me yesterday and i did the battery trick and drove back home fine.
PLEASE, i beg you guys, PLEASE help / assist me to solve this issue and not just read and leave, as i love my car alot and would love to drive it without and headaches!
Hope someone who has experienced this before or has some experience in solving such issues can help me out!
After numerous 02 sensors I took it back to the shop an they said the sensor cord tht comes off the motor into the 02 sensor came undone trace your 02 sensor wire to the engine make sure there is no loose connections thankfully that was all tht was wrong with mine. Hope this helps good luckJust do what i did and get a new PCM and it will fix the problem, but before doing that try the cheaper options first which is Camshaft sensor, crankshaft sensor, check your MAF sensor is clean, make sure your throttle body is clean.
Do those little sensors one by one till it solves the issue, if it doesnt then it means its your PCM has gone faulty, mine was a Faulty 02 sensor heater circuit driver in the PCM was bad. No issues since replacing the PCM.
Oh wow luckily it wasn’t something tricky like mine was! LolAfter numerous 02 sensors I took it back to the shop an they said the sensor cord tht comes off the motor into the 02 sensor came undone trace your 02 sensor wire to the engine make sure there is no loose connections thankfully that was all tht was wrong with mine. Hope this helps good luck
have you fixed your problem yet ?Im on the same boat as you too, does the same thing but doesnt die, it just literally rocks the whole damn car, but i realized that i have a leak in mid magnaflow muffler, my tuner says that could be affecting my engine's performance, another guy says thats not the cause because its way downstream from the engine. I've attached the picture of the leak, not sure if this mid muffler / resonator leak will cause an engine to throw a P0300 code and bank 1 rich?