Misfire
08-16-2009, 10:33 PM
#1
5th Gear
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Misfire
I have a 1999 c5 that recently started missing and the valves rattle under hard acceleration. Check engine light came on and had the codes read. They were P0301,P0302,P0303,P0304,P0305,P03036,P03 07,P0308 (coil primary/secondary misfire). I put all the coil packs from my fathers 02 Z06 on mine but still has misfire. Then I changed the plug wires and plugs sill misfires. I also changed the fuel filter but still misfires. Codes on DIC are c1255 / u1016h / u1064h / u1096. Have looked up codes but cant find any place that explains what it all means. Car runs good at idle no misfire, car also will cruise at 90 mph with no miss.
08-17-2009, 12:49 AM
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Wounded Warrior Escort '11
Just in case, on the rear of the driver's side head is a ground connection(s). You want to make sure its tight. They have come lose before.
08-17-2009, 12:07 PM
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
08-17-2009, 06:17 PM
#6
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At some point you are going to have to get a pressure gauge on the rail to confirm adequate pressure. Considering all cylinders are misfiring, I'd start looking for common denominators. All the ignition coils ground at the same point: G107, located on the back of the drivers side head. Inspect this ground for security. Also, check the resistance value at any ignition coil pin A to ground with a DMM.
Since you have no info in your sig, I don't know if you have headers or not, but I'd still inspect the crankshaft sensor wiring for damage.
Since you have no info in your sig, I don't know if you have headers or not, but I'd still inspect the crankshaft sensor wiring for damage.
Last edited by lucky131969; 08-17-2009 at 06:20 PM.
08-18-2009, 10:20 PM
#7
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Took car to dealer today, hate to see the bill, fuel pressure is at 40 psi. They are checking other things. I ask if it might be the PCM he said maybe he hadn't got that far yet.
08-18-2009, 11:02 PM
#8
Safety Car
08-18-2009, 11:08 PM
#9
Race Director
08-21-2009, 10:01 PM
#11
Melting Slicks
At some point you are going to have to get a pressure gauge on the rail to confirm adequate pressure. Considering all cylinders are misfiring, I'd start looking for common denominators. All the ignition coils ground at the same point: G107, located on the back of the drivers side head. Inspect this ground for security. Also, check the resistance value at any ignition coil pin A to ground with a DMM.
Since you have no info in your sig, I don't know if you have headers or not, but I'd still inspect the crankshaft sensor wiring for damage.
Since you have no info in your sig, I don't know if you have headers or not, but I'd still inspect the crankshaft sensor wiring for damage.
I'm 100% convinced that the folks on this forum know as much if not more than GM about this car!
08-21-2009, 10:11 PM
#12
Race Director
Some of the guys on here are pretty good at zeroing in on items that may be the cause of the problem.
Last edited by ajg1915; 08-21-2009 at 10:24 PM.
08-22-2009, 11:43 AM
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08-22-2009, 03:39 PM
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When I spoke with the tech he said that he found this by luck due to moving wires while his meter was hooked up. They checked the PCM, fuel pressure, etc. The dealer charged me $450.00.
08-22-2009, 03:46 PM
#16
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I'm sorry to hear that. G107 would have been the first thing I checked. I would scratch that dealer off your listed....
08-23-2009, 09:47 PM
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You would think that the Chevy dealers would make sure that they had a tech that knew their stuff when it came to service on their number 1 sports car. Does any one know a good tech for the C-5 Corvette in the area of Kingsport, Bristol, Johnson City, Tennessee.
08-23-2009, 10:24 PM
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
Yea,,,you would think so but,,,,,you would be in for a real surprise. If it isn't in a trouble flow bubble chart,,,most of them cant fix crap! Ive seen them replace stuff that had NOTHING to do with the problem and then try to convince the person that it needed to be replaced anyway.
One of the things that not many people know is, many of the things that a Service Center replaces, can easily be fixed for nothing!
Like the ignition switch. Easily fixed but,,,,,,,GM wont fix it. You got purchase a new one. Free self fix vrs $70 switch + Labor to remove the old one and install the new one.
Cant tell you who to use down there but, hope you get some guidance.
BC
