shawn_85gt

Sometimes when I'm diving, the tachometer drops to zero but all the electrical components in the car stay on. If I don't catch it in time, and put it in nuetral, it backfires really bad. Also, occasionally when I start the car, it idles regularly, but when I press the gas pedal, th tach bounces all around from about 700 rpm to 0 rpm. After a few times of turning the car off and back on, it seems to fix itself and not act up again for a couple of days. The first time it happened, I took the air cleaner off of the carb and it stopped untilI put it back on, so I bought a new air filter, which seemed to fix the problem for about a week. The past couple of days, it has been happening more frequently. The carb is a holley 600cfm andonly 6 months old.

Gary H

If you have the stock coil, check the horseshoe from the wiring harness that attaches to the coil. They will break where they attach to the horseshoe. Check the rest of the wires too.

shawn_85gt

The coil is a MSD Blaster 3. As I was looking over the car, I found a small balled up piece of electrical tape stuck in one of the vacuum lines. The car ran fine for the past few days, until yesterday it acted up again. I went to see if there was any loose wires, and as soon as I touched the wiring harness the idle changed to normal. I didn't notice any broken or loose wires, and it has not done it again yet.

Gary H

Start checking the wires then, you probably have a broken one. Look at the connection to the ignition module too.

shawn_85gt

I'm pretty sure the touching the wires was a coincident. It acted up real bad yesterday, and left me sitting on the side ofthe roadfor a few minutes until it calmed down each time. When it did it this time, I checked the wires and made sure all connectors were tight, everything looked fine and nothing let it run better. It seems to do it more often when I accelerate hard, and if i leave it in gear and let it backfire, that usually fixes it for a bit. If I don't leave it in gear, then it just idles really bad and I have to wait a few minutes before I can continue driving.