LT1 running rough.... optispark?

[montemadness04]

So 95 transam LT1 with ramair ....72k miles.... slp fans... 160 tstat .... last owner says it has a newer distributor on it already (but not sure how long ago or the parts used)

car runs really rough during acceleration and has a vibration within the whole car after warmup... takes about 10 minutes to start having problems... normally very responsive throttle now seems to lag with a major power decrease.... almost seems like its misfiring or a possible transmission slip ....

we've been trying to diagnose it ourselves but wondered if anyone had a similar problem or thinks its a textbook problem they've been through b4 ..... we've already tested the ignition coil and ignition control module... both are working fine.... not really looking forward to tearing the whole front of the car apart to get to the distributor and since its been replaced recently (according to previous owner) were thinking that might not be the problem....

any ideas?

[JoeliusZ28]

check your spark plug wires. Here is a video of my car with a similar problem - and the fix was the spark plug wires. I had 2 sets of aftermarket wires do this, and it finally went away when i switched back to AC Delcos!

Also, optis are a little bit weak when it comes to producing spark, which is one of the reasons aftermarket wires gave me more problems than they should have. (another reason was my own fault, crappy crimp job). For this reason I was told to minimize the resistance as much as possible. Run a cooler spark plug like TR6, and also gap them conservatively... doing this made a noticeable improvement on my car even after i fixed the issue with the wires.

[98blackbeauty]

egr still on the car? your symptoms are classic description of bad egr valve. or air pump or hose bad.