pa_hmfic

I have seen a number of different posts with regard to misfires on bank 2 with the chevy camaro 5.7L

I now have the issue with a vehicle I am working on and need help. Info is as follows.

2000 Chevy Camaro 5.7 L

Cylinder 4 and 6 basically dead but coils and plugs are firing, injectors are clicking, and noid light test shows proper electrical function to the injectors and coils. Compression checks ok in both cylinders. As car misfires, unplugging coil 4 an 6 makes no difference. Swapped coil 4 with coil 2 and still same problem

Bank 2 is running negative fuel trims while bank 1 with no misfires is positive fuel trims. Bank 2 O2 sensors are reading high with limited fluctuation. Bank 2 O2 sensor 1 reads over 0 prior to cold start and upwards of .8 while running. Bank 2 sensor 1 reads 0 prior to cold start and operates around .5 as normal while running.

So cylinder 2 and 8 misfiring in the hundreds, cylinder 4 and 6 misfiring in the high thousands at the same time.

New plugs, new wires, same problem with previous plugs and wires.

I am leaning towards the Bank 2 sensor 1 O2 being bad, just not sure how it could cause this problem. Only other thought is possibly clogged injectors on cylinder 4 and 6 even though they are clicking.

Probably will swap front O2's side to side to see what happens but running out of ideas.

Anyone have any constructive input????

Thanks in advance!

JakeRobb

How have you determined that #4 and #6 are misfiring? Is the PCM throwing any codes?

pa_hmfic

Determined Number 4 and 6 misfires from modis scan tool misfire counts as well as unplugging coils while running with no change. 2 and 8 misfire as well but very low counts as compared to 4 and 6. 6 is worst around 9000, then 4 around 8000, then 2 and 8 running around 500 and 600. The car shakes really bad at idle like a dead miss, 4 and 6 make no difference. Unplugging any other coil makes it worse.

Only codes have been a consistent p0300 random misfire, a p0356 when I forgot to plug back in the number 6 coil. Early on there was a history code for MAF "A" circuit range/performance but this code has not come back for 3 weeks while testing, and all readings from the MAF seem to be consistently within spec and what I would expect to see.

JakeRobb

Just a guess: carbon buildup in the cylinder?

pa_hmfic

I doubt we have a carbon issue.

I am going to do an injector balance test when time permits.

If no issue injector wise, I will follow up by swapping the 1st O2 sensors left to right and see what happens.

Then go from there.

Gillespie1082

please report back with your findings. i have the same issue just flipped. my 2,4,6,8 bank is running insanely rich in long term trim at 25 wile short term is around 4 and the other side is about 4 long and short term. p0300 and p0302 are the consitant codes i get.
what i have done so far in case your interested (all of this was before i had a good enough scanner to see the trim.) all new wires plugs and new opti. switched the problematic cylinders injector with a known good one. miss did not move. compression was good in the cylinder and leakdown was ok also... that sounds about it. i will do my best to reply back if i find anything further or if i atleast come across some new ideas. best of luck