need help, car missing bad!!!!!
Thread Starter
Racer
Joined: Jul 2006
Posts: 277
Likes: 1
From: waco tx
need help, car missing bad!!!!!
ok i drove the car 60 miles to put it on a dyno and the car has never missed or anything always ran good. but ive never driven it more than 15 miles or so at a time. but got to the shop changed plugs and wires put it on the dyno and i was missing bad. so on the drive home at first i didn't notice it but by the time i got home i couldn't accelerate at all. studdering and missing like crazy. what does this sound like. fuel pressure is steady, and i check the wires. could a bad plug do this? i gapped them all the same @35. maybe a coil?
car is a 98 c5 m6 402 with d1sc
car is a 98 c5 m6 402 with d1sc
Racer
Joined: Dec 2007
Posts: 354
Likes: 4
From: Grand Ledge Michigan
You gave the best diagnostic clue of all "changed plugs and wires"
I'll assume you bought new wires and didn't put a previously used set back on, because if you did, they can get damaged when pulling them off. Go through plug wires one by one, more than likely not plugs unless you broke and insulator when installing them. Did one plug give you fits in the socket?? Socket square on the plugs when you were tightening them?
I'll assume you bought new wires and didn't put a previously used set back on, because if you did, they can get damaged when pulling them off. Go through plug wires one by one, more than likely not plugs unless you broke and insulator when installing them. Did one plug give you fits in the socket?? Socket square on the plugs when you were tightening them?
Tech Contributor
Joined: Jan 2007
Posts: 19,359
Likes: 1,127
From: Dyer, IN
You gave the best diagnostic clue of all "changed plugs and wires"
I'll assume you bought new wires and didn't put a previously used set back on, because if you did, they can get damaged when pulling them off. Go through plug wires one by one, more than likely not plugs unless you broke and insulator when installing them. Did one plug give you fits in the socket?? Socket square on the plugs when you were tightening them?
I'll assume you bought new wires and didn't put a previously used set back on, because if you did, they can get damaged when pulling them off. Go through plug wires one by one, more than likely not plugs unless you broke and insulator when installing them. Did one plug give you fits in the socket?? Socket square on the plugs when you were tightening them?
Yep, no rocket science here. Go over your work, you probably have a loose wire or cracked plug.
Thread Starter
Racer
Joined: Jul 2006
Posts: 277
Likes: 1
From: waco tx
well i check all wires, but havent pulled any plugs. i thought if maybe a coil was close to goin out the long drive would have finished it. also it wasnt doin it as bad at first, it just kept getting worse and worse. i figured if it was a plug or wire it would have been the same the entire time, not get worse
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
What wires did you put on? How did you check the wires? Did you just check to see if they were on good, or did you actually check to see if a spark was getting through to the plug?
It is possible you got a bad wire right out of the box. Since changing wires and plugs started the problem, most likely the solution is there somewhere.
With the engine running, you should be able to tell if the cylinder is firing by checking how hot the exhaust manifold from that cylinder is.
It is possible you got a bad wire right out of the box. Since changing wires and plugs started the problem, most likely the solution is there somewhere.
With the engine running, you should be able to tell if the cylinder is firing by checking how hot the exhaust manifold from that cylinder is.
Le Mans Master
Joined: Nov 2005
Posts: 6,993
Likes: 25
I just did plugs and wires-what plugs/gap did you use? And by the way-if you were on the dyno and missing badly-why could nobody there diagnose this?? You probably have missfires all over the place. Think you need a new "dyno" shop too.
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Thread Starter
Racer
Joined: Jul 2006
Posts: 277
Likes: 1
From: waco tx
well i dont think its throwin any codes, no check engine light and i just bought the car and texas speed did all the tuning and they locked the damn comp!
Pro
Joined: Sep 2008
Posts: 713
Likes: 2
From: Tennessee
Well depending on how far you drove it, it could have possibly fuel fouled out one of the plugs since there was no spark gettin to it through a possible disconnected wire. If all the wires are connected and there is still a miss, could be the culprit.
Drifting
Joined: Aug 2006
Posts: 1,523
Likes: 34
From: King George Virginia
It sounds as though you are loosing a coil pack. I had the same thing happen on my Lightning. It would idle fine but as soon as a load was placed on the coil pack it started misfiring real bad. Check your coil packs.