I did a full detail on my 99 GT the other day and started having some issues. I cleaned the engine with some engine cleaner, rinsed, then started it up to let it run at operating temp while I washed the rest of the car. It ran fine. A couple days later I headed to the store about five miles away, ran perfect. Then, just a day later it started running really rough, power cutting out, and I was getting that egg smell like the catalytic converter was plugged. The service engine soon light came on so I pulled the codes with my Superchips, looks like cylinders 7 and 8 are misfiring.

Im assuming the rinsing of the motor screwed things up, but it could be coincidence. What should I be looking for first to fix my issue?

Thanks guys!

 

I've used a pressure washer to wash a number of different mid 90's to mid 00's Ford engines and the only one I ever had an issues with was my best friends 01? F-150 which I had promised him nothing would happen with. Must have gotten a little water in between one of the cops, it sat for a couple days and was fine.

Another possibility and what my guess would be is that you might have bad coils for those cylinders. My friends truck had just had a misfire the week before, and we changed the coil for that cylinder and the problem was solved. Hopefully this helps a little bit.

 

95% most likely its wet COPS......

 

Fogive my ignorance....but what is COPS? Coil On Plugs?

I removed the coil from plug 7 and 8....nothing looked wet. I blew out the plug area with air and hooked everything back up. Still misfiring, but it isn't throwing a code yet. It seemed to do fine in Park (automatic) but when I shifted to Drive it started misfiring again....and now it continues to do it in every gear after that. The plugs all looked dry, the spark plug area was dry...but maybe the actual coil internals got wet?

Its been 95 degrees the past several days around here, hard to believe it wouldnt have dried out in that time....though it is in the garage so its cooler.

 

Yes, it's Coil on Plugs. If you've let it sit for a couple days and it still is misfiring I would say its probably bad coils. Thats exactly what my friends truck did when it was misfiring. Hardly noticeable in park, but you put it in drive and there was no missing it.

 

Classic clean engine vs. engine that runs well scenario.

 

You my have burned the COPS up when they were wet. I went thru 3 trying to clean up my Crown Vic PI.