Glyn M Ruck

First signs of a bad O2 sensor are engine stumble on acceleration.

Air leak in any vacuum pipe or the Captive crankcase ventilation system should cause the vehicle to run lean. If it can't compensate sufficiently it should throw a fuel trim code.

I would replace all plug wires first.

holycaoAMG

updated codes this morning:

P2001- Random Misfire
P2052- Misfire cylinder 5
P2054- Misfire cylinder 2
P2056- Misfire cylinder 3
P2082- Left O2 Sensor Short Circuit

Im switching out the wires as i am typing this. lol

Glyn M Ruck

This is all looking plain now. Replace both upstream O2 sensors & all wires to start with. Pray the coils are OK.

holycaoAMG

Ah, finally. Just finished up changing the wires in all cylinders. Ran smooth for a bit, then engine started to stumble after 5 mins of driving. Went back and inspected and cleaned all plugs/wires again, clean the throttle body, MAF, and air filters. Started her up and she was running normal.

Drove for a bit longer and bam, no signs of misfire or hesitation.
During idle, in gear, or under WOT... she ran smooth as butter. (not to mention i feel it running a lot stronger too)

Let the good times roll, gentlemen.

Glyn M Ruck

Good news! - You had better start budgeting for those O2 sensors.

Bree Kemp

my C180 would shut down cylinder 3 when idle, fine if you kept revs up. Back to normal when ignition turned off and back on. It turned out to be a leaking exhaust! New exhaust, problem solved.

nmpaulcp

My 2003 c240 4matic Idles fine in neutral or park, rough when in drive, especially when steering wheel is off center. Throttle body is clean. new plugs, wires, no vacuum leaks, new motor mounts, new fuel filter. Fuel injectors were cleaned. No codes either.
Only issue I can see is fuel pressure is at 51 maybe 52 PSI not at 55 when starting or idling, does not change when reving engine. Is this too low? I think it should be 55 but I am not sure if this is enough to affect it.
Any comments?