Hello all,
I have a 98 Expy and washed the engine compartment. The engine now misses pretty consistently, all rpm ranges. Concurrently had a battery go bad and the starter died too, not sure if they are related at all. Not throwing any codes. Took the truck to the shop and they checked all the coils and replaced the dead starter, all the coils tested good. What am I missing?
Thanks for looking.
Rob

 

You likely got water in one or more of you COP boots. Dialetic grease is your friend in this situation. Same thing happend to me a couple of years ago after washing my engine.

 

I agree with Mike, you need to dry out each boot before they begin to corrode and use some dielectric grease inside each boot. Corrosion will quickly take them out! Been there, done that!

 

One or more of the boots on the bottom of the coil has a split in it. Water gets into the split and acts like a conductor allowing the spark to jump to the side wall. Your best bet is to grab a set of replacement boots for about $25 and dielectric grease. Replace the boots and use the DG inside them before you reinstall the coils and you'll be good to go.