Sound like a bad coil?

[Blackened300a]

Here's my issue, My engine hasn't been 100% as smooth as before. That's understandable due to the new pistons and the rebuild. Saturday I took the car out and really put it through the paces, I did a WOT 0-80 run and just drove the car a little harder then usual to make sure nothing comes apart. When I got to my shop the engine ran silky smooth like glass. I had to look at the tach cause I thought it stalled, that's how smooth it idled. The car cooled down and when I restarted it and I had the same rough idle from before.
I havent changed the coils, just the plugs are new. I have new coils ready to go from musclemerc (thanks again!) Im just curious if thats what the idle problem could be before I throw them in.

Thanks for any info.

[ctrlraven]

Do you have GMS coil connectors? If not you should!

[Vostok]

I think ive been having the same problem. Do you kind of hear a misfire at the exhaust tips or smell gas?

[Krytin]

That does not sound like coils. Spark plugs maybe.
Some vacuum leaks seal up from expansion when they get really hot - i.e. after an 80 mph run!
Have you tried an either test when the engine is running rough?

[Blackened300a]

Do you have GMS coil connectors? If not you should!

Yes I do.


I think ive been having the same problem. Do you kind of hear a misfire at the exhaust tips or smell gas?

The exhaust sounds normal out both pipes. I don't hear a stumble or anything like that. No gas smell either.


That does not sound like coils. Spark plugs maybe.
Some vacuum leaks seal up from expansion when they get really hot - i.e. after an 80 mph run!
Have you tried an either test when the engine is running rough?

No, we did do a smoke test when we tried to find a vacuum leak for the HVAC and that came up clear. I may try the either test this weekend if the coil swap don't help.
I took the car out Saturday night and drove it hard as well and it didn't clear up. Im thinking its a intermittent miss in one of the coils. I hope to find it this weekend. Last ditch effort will be to pull the Spaz intake off and see if it cracked again.

[Krytin]

I forgot about the intake - hope that's not the case!

[musclemerc]

Paul, I went for a ride in MM_BLUE's car and he has the same stubble at idle and a loss in power. He's comming over next weekend to get new coils and plugs installed hopefully this will remedy his problem. According to other members the issue your describing is a bad coil . Put them in and let us know.

Good Luck!

[Blackened300a]

Paul, I went for a ride in MM_BLUE's car and he has the same stubble at idle and a loss in power. He's comming over next weekend to get new coils and plugs installed hopefully this will remedy his problem. According to other members the issue your describing is a bad coil . Put them in and let us know.

Good Luck!

I dont have a loss in power though. Its running strong just the idle.