My 99' will run rough (like a cyclinder is misfiring) about 5% of the time. When I notice this happening, I'll turn off the car and restart it. Most of the time it will run perfect after doing this and other times it continues to running rough until the next time I stop or the next day. The car has 70K on it and a just had a tuneup around 60K. Any ideas about what is going on?

 

coil packs?

 

If your plugs were changed in the tuneup (most likely) and most other precautionary measures were taken (new filers/fluids) then i would say that one of the engine coils is going bad.

 

As I'm sure you know the 4th gens are famous for having bad coil packs. I would test the packs individually and see if they are making spark.

 

The 99's were known for bad coils from the start.

 

What's the best solution to this problem? I'm going to keep this car for a long time. Should I just go ahead and replace all six coil packs or just replace them as they go bad? What are the best packs to get so this problem is fixed for good?