p0300 help needed. 05 Corvette LS2
11-02-2012, 07:10 PM
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p0300 help needed. 05 Corvette LS2 I've got a p0300 misfire on a 05 Corvette. I logged it on my drive home and 2,4,6,8 misfired anywhere from 1000-3000 times per cylinder. 1,3,5,7 misfired between 0-100 times. I'm pretty sure the passenger side is the root of the driver side miss because its pulling 15* timing to compensate. So looking for info on what would make 2,4,6,8 go crazy like that.
So far I have swapped coil packs, checked plug gaps, swapped plug wires, unplugged o2 sensors to see if it had any effect. Nothing helped. Car does semi OK at start up and progressively gets worse especially at higher rpms. It holds 60psi fuel pressure at idle and 60psi at 3k.
Any advice would be greatly appreciated.
So far I have swapped coil packs, checked plug gaps, swapped plug wires, unplugged o2 sensors to see if it had any effect. Nothing helped. Car does semi OK at start up and progressively gets worse especially at higher rpms. It holds 60psi fuel pressure at idle and 60psi at 3k.
Any advice would be greatly appreciated.
11-02-2012, 07:13 PM
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A little extra info. The car was brought to me in rough condition. It wouldn't start, (ended up being a loose connections to the computer) needed plugs and a couple plug wires had burn marks and needed replacing.
So now the car runs but it just runs like crap.
So now the car runs but it just runs like crap.
11-05-2012, 06:04 AM
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just unbolt the cats and run it and see if its better or get a backpressure gauge and check it that way. Not to many other things will affect only 1 side. Other than a bad coil ground or something
11-07-2012, 08:04 PM
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Ok i started messin with the car a little more tonight and logged some info. I don't even know if the o2 sensors are the problem but I was getting some odd readings.
I swapped the rear 02 sensors before I logged this data to see if it would effect anything.
o2 Sensor Heater Amps:
B1S1: .82 - 0 repeatedly
B2S1: .82 - 0 repeatedly
B1S2: .52 - 0 repeatedly
B2S2: .52 - .54 repeatedly (never went to 0)
o2 Sensor Mv
B1S1: 109 - 760 very rapid change
B2S1: 69 - 777 very rapid change
B1S2: 800 - 816 slow with little change
B2S2: 490 - 760 rapid change
Misfires at idle for 1 minute:
Cyl 2 - 8
Cyl 4 - 11
Cyl 6 - 115
Cyl 8 - 0
That was with the car running for 1 minute. After twenty minutes i took readings of the driver side
Total misfires in 20 minutes of idle:
Cyl 1 - 10
Cyl 3 - 0
Cyl 5 - 11
Cyl 7 - 1
I did drop the driver side cat to change the o2 and it looked clean. maybe I should drop the passenger side and see if its stopped up. Also how would the coils get a bad ground, where do they ground?
I swapped the rear 02 sensors before I logged this data to see if it would effect anything.
o2 Sensor Heater Amps:
B1S1: .82 - 0 repeatedly
B2S1: .82 - 0 repeatedly
B1S2: .52 - 0 repeatedly
B2S2: .52 - .54 repeatedly (never went to 0)
o2 Sensor Mv
B1S1: 109 - 760 very rapid change
B2S1: 69 - 777 very rapid change
B1S2: 800 - 816 slow with little change
B2S2: 490 - 760 rapid change
Misfires at idle for 1 minute:
Cyl 2 - 8
Cyl 4 - 11
Cyl 6 - 115
Cyl 8 - 0
That was with the car running for 1 minute. After twenty minutes i took readings of the driver side
Total misfires in 20 minutes of idle:
Cyl 1 - 10
Cyl 3 - 0
Cyl 5 - 11
Cyl 7 - 1
I did drop the driver side cat to change the o2 and it looked clean. maybe I should drop the passenger side and see if its stopped up. Also how would the coils get a bad ground, where do they ground?
