I have been having issues with my car stumbling in the higher rpm's lately and it has just turned off on me a couple of times as well while driving down the street. When it turns off or will not run properly I jiggle the spark plug wires at the coil packs and it runs fine. I am going to try new wires first but was curios if the coil packs themselves are replaceable and if so what is compatible with them.

Thanks

The coils can be replaced with coils from a Buick Grand National or early Cadillacs that had that style coil. Trouble is we match the coils sets that are installed on those units and the matching is somewhat critical. Additionally, the replacement coils available at the auto parts store tend to be somewhat low quailty and won't really last on our systems. If you can find a set real GM coils on a car in a junkyard or get a set from the dealer that would probably be ok. But I would recommend sending the system to us and having it checked over and the coils replaced here if possible.

I'd follow Jon's advice. If you want to investigate it a bit, I'd remove the two screws that fasten each coil, then pull up on the coils to remove them, then get yourself a piece of emery cloth and clean the flat blade posts that the coils fit onto, then clean everything and tighten them back down nice and tight. It's free, and it might be the problem.

If that don't help, then it's back to what Jon said....

OK thanks for the info. I am definitely going to try new plugs and wires since it has been at least 4 years since either have been changed. I will also try taking them apart and cleaning them as suggested. How much does it cost to test the unit and repair it if necessary? what is the typical turn around time?

Turn around depends on backlog. I don't THINK we're too busy right now. I don't know about cost, give Uwe a call and he can give you a heads up on that.