So how rough will a car run when the leading coil craps out?

At the track, the car started to sound a little off part way through a session, pull into the pits and the idle is rough, about 10 inches instead of my usual 15 motor is not smooth at all. I immeadiatly figured an apex seal went. Drove the car home from the track and the idle was always poor but the car would sometimes drive silky smooth and other times be really rough. also boost response is way down but power is still good. Pull the leading plug wires and the car will still start and idle about the way it was except was only pulling 8 inches. Then pull the trailing wires, cant even start the car...

Any thoughts.

 

Look in the service manuak. Coils are easy to test. I believe resistance of over 1 Ohm is bad.

 

The coil is bad, im just trying to figure out if thats my only problem...
Im really being lazy and not doing a compression test just yet.