[Rainfarer]

Originally Posted by ctrlz

Your purge solenoid for the EVAP system may be stuck open. This will cause a rich condition. This video explains replacement for an older car, but the ideas are the same.
EDIT: Just looked at the repair manual. purge solenoid is very easy to get to on the V6. Looking toward rear of the car, it is just left of the throttle body and looks similar to the older one in the video. You can try disconnecting and capping the lines to see if it changes your fuel trims. That is probably easier than testing the solenoid.

Thanks for the suggestion, but that looks like a check engine light type of issue and I don't have any DTCs in the system at all. I will check it nevertheless

[Rainfarer]

Also is it okay for o2 sensor to have such fluctuations across the board? Shouldn't it be more smooth or something?

[ctrlz]

O2 sensor could be the problem.
Do you have left and right on the V6, to compare the readings?

[Rainfarer]

Originally Posted by ctrlz

O2 sensor could be the problem.
Do you have left and right on the V6, to compare the readings?

I will check it in a couple of days, I'm out of town for the most part of this week. But my bet is on o2 as well now

[CYN_CRVR]

Still troubleshooting?

[Rainfarer]

Originally Posted by CYN_CRVR

Still troubleshooting?

Yeah, it's currently on hold - the car is half-stripped. I've decided to remake front seats in leather (I have a basic gray interior), one thing led to another and I'm redoing the whole interior) But good news - it's gonna be gorgeous

[Taliyahk]

Originally Posted by CYN_CRVR

Need more info:
- How many miles on your engine?
- Do you have any power mods?
- Stock or aftermarket tune?
- Did this behavior begin suddenly out of nowhere? Or has it gradually gotten worse over time? Did you recently change your setup, or perform maintenance?
- Does the engine smooth out while accelerating, or does it still occasionally skip while driving?

An engine needs air and fuel in the right proportion, plus a correctly timed spark to operate smoothly, so your problem might be:
Air: vacuum leak in the intake system, or bad MAF sensor
Fuel: clogged fuel injector or low fuel pressure
Spark: bad spark plug or electrical issue
Also, a bad O2 sensor, or an exhaust leak near or upstream to an O2 sensor could throw off your air-fuel ratio and cause issues.

Years ago my C5 Corvette began to experience an occasional misfire. After detecting a drop in fuel pressure, it was eventually traced to a bad fuel pump wiring harness. It was an unusual issue that my builder hadn't seen before.

I am currently having this issue however I believe this all started happening because of my AFM delete plug, I unplugged it and plugged it back in as the car was on and this is when the p0420 code came up and my car started skipping every so often when cruising, it's misfiring in cylinder 3 (according to a shop I took it too)... Any ideas of what it do to fix it or if those two problems have a relation to each other?