Hello all

Need help diagonosing a problem, my 00 z28 camaro is misfiring when in drive and stopped sometimes while in park to, took it to the mechanics they ran diagnosis said that cylinder 4 was misfiring 1400 times with others misfiring some, and said I was running rich. They replaced plugs and wires, i checked the o2 sensors with some abnormal readings I believe, bank 2 constant voltage at .8v which i think is normal but bank 1 sensors anywhere from -.4 to +.8v while driving. Thinking it maybe a bad injector as this started after I first got the car wasnt thinking and put 87 octane gas in it then switched to 93 right after. Anyone have any ideas?

Thanks

 

you got it backwards bro the constant switching from high to low that bank 1 is doing is what you should see. the constant high from bank 2 is whats out of line. somewhat to be expected when cyl 4 is misfiring that much being that its on bank 2 and that means a lot of raw fuel is making it into the exhaust causing the rich reading all the time. 87 octane fuel shouldnt cause the injector to clog and if it had you'd expect to see it across the board to some degree. pull the plug and make sure its gapped properly and the wire is connected corectly

 

Thanks noma for the reply,

I popped the hood at night to see if there was any arching at the suggestion of someone else but didnt find any sparks, I also ran a test through a obd 2 scanner and this is what it came up with,

Test report:
------------------
TID:$02 CID:$04
- Lean to Rich sensor threshold voltage(constant)
Test incomplete or dependant test failed
--
TID:$02 CID:$10
- Lean to Rich sensor threshold voltage(constant)
Min: 90
Test result value: 90
PASS
----
TID:$02 CID:$11
- Lean to Rich sensor threshold voltage(constant)
Min: 375
Test result value: 376
PASS
----
TID:$02 CID:$12
- Lean to Rich sensor threshold voltage(constant)
Max: 343
Test result value: 46
PASS
----
TID:$02 CID:$20
- Lean to Rich sensor threshold voltage(constant)
Max: 180
Test result value: 7
PASS
----
TID:$02 CID:$26
- Lean to Rich sensor threshold voltage(constant)
Max: 70
Test result value: 8
PASS
----
TID:$02 CID:$30
- Lean to Rich sensor threshold voltage(constant)
Test incomplete or dependant test failed
--
TID:$02 CID:$31
- Lean to Rich sensor threshold voltage(constant)
Max: 120
Test result value: 65,530
FAIL
----
TID:$02 CID:$40
- Lean to Rich sensor threshold voltage(constant)
Test incomplete or dependant test failed
--
TID:$02 CID:$46
- Lean to Rich sensor threshold voltage(constant)
Min: 100
Test result value: 100
PASS
----
TID:$06 CID:$35
- Lean to Rich sensor switch time(calculated)
Max: 71
Test result value: 59
PASS
----
TID:$06 CID:$41
- Lean to Rich sensor switch time(calculated)
Max: 118
Test result value: 35
PASS
----
TID:$06 CID:$55
- Lean to Rich sensor switch time(calculated)
Max: 78
Test result value: 49
PASS
----
TID:$06 CID:$61
- Lean to Rich sensor switch time(calculated)
Max: 220
Test result value: 48
PASS
----
TID:$07 CID:$0c
- Minimum sensor Voltage for test cycle(calculated)
Max: 0
Test result value: 65,491
FAIL
----
TID:$07 CID:$0d
- Minimum sensor Voltage for test cycle(calculated)
Max: 1
Test result value: 65,534
FAIL
----
TID:$0c CID:$20
- Misfire counts for last/current driving cycles(calculated)
Max: 407
Test result value: 53,707
FAIL
----
TID:$0c CID:$30
- Misfire counts for last/current driving cycles(calculated)
Max: 302
Test result value: 53,726
FAIL

speaks a foreign language to me except the o2 sensor reading. If someone else can decipher all that please do. Ive parked it for now and will pull the plug wire and coil pack off this weekend and see what I get.

Thanks for the help again

 

Can you post the codes that you're getting? What you're posting really isn't telling me much. Its just showing a status of the monitors. Basically you said you have a missfire on 4 and your getting a rich code. Well, you're going to get a rich code because 1 cylinder is miss firing. As far as the O2 sensors, that not what the problem is so don't even pay that any mind. Now as for the miss fire, you mean to tell me they changed plugs and wires and you still have the miss fire? Did they check the coil on that cylinder? You also said that they said other cylinders were miss firing. If this is the case a P0300 would set for a random miss fire. This tells me the problem is most likely in the fuel delivery system, such as a clogged fuel filter or a bad pump. I wish I can help ya out and have you come to my shop but you're more then 1000 miles away. If they did the work and returned the car back to you with a miss without telling you whats going on their ******* morons.

 

Yeah tell me about it especially since they charged me 600 bucks just to change plugs wires and fuel filter, the odd thing about it is, it is not throwing any codes, no CEL light went off, I even checked to make sure maybe the light was malfunctioning but no hidden codes or historic codes either, I know for sure they didnt check the coil pack so thats where im starting this weekend gonna switch the coil pack with a different cylinder and see if that cylinder starts misfiring, if not I start looking at the injectors and hope its not the pump

Thanks again