My car is running/idling roughly, can smell fuel smell seems running rich, lots of black carbon on spark plugs, exhaust pipe etc..
Also, engine stalls at sudden braking, low speed, turning, stopping at signal. The stalling issue is very random, it could happen anywhere in the middle of the road. RPM needle is not stable when this happens. The needle jumps up/down like surging. Car is struggling to maintain 500+ RPM at idle, low RPM issue. I have P0050 error reported (O2 Heater circuit malfunction) on Bank-2, sensor-1. Could this be the problem? any help is appreciated.
I have changed:
1- Spark plugs twice
2-Coil Pack
3-Cleaned injectors with cleaner after dismantling the plenum
4- replaced gaskets for both plenum and intake manifold
5- did catalytic system cleaning process
6- ensured no air is being leaked
7- cleaned throttle body
8- cleaned MAF
9- Replaced MAF
10- replaced vacuum pipe connected to air intake tube. as it was unplugged/broken
I'm suspecting whether the O2 sensor is the culprit of all this? if not ECU? I'm pretty much out of options.