I don't get it, I've been cleaning engines for ages and NEVER had this problem. Last night I cleaned the engine on my moms 01 Harley Davidson F-150 (5.4l ). Just to remove old fluid stains and make sure nothing is leaking. I didn't get the alt wet. I soaked a few areas with simple green then carefully hosed it off up close so I wouldn't get everything wet. I had it running before hand, then had to shut it off because the clutch fan was drying it off too fast. When I got done, I started it up. Immediatly it started missing, seemed rather light at first. It would miss a little then stop, then start again like a coil had a bad connection. I sprayed all the coils and injectors with quick drying electronic parts cleaner hoping to dry out any water. Still missing. I decided to drive it around for awhile to hopefully let the heat dry it out. Once I put it in gear and started driving, then I really felt it missing. It was making the tranny shudder in and out of gears. It felt like at least 2 different coils were screwing up. After some time driving (about 30 minutes) , a lot of the miss cleared up. I got it to idle normally without hesitation. Seems like it's normal, but if I put it in gear , it lacks power and will start missing if I step on the gas harder. In neutral, revving it up, there is a delay and I can feel it shudder and start to miss for a second. Under light loads, it doesn't miss now and seems normal, but it lacks power. What's up with this? I have cleaned engines off dozens of times. Even cleaned off this engine 2 other times several years ago and I didn't have this problem. Coil packs don't need to be covered because they are sealed. Could the seal on a them be going (90k miles) or is there some bad wiring or some other sensor on these engines I am unaware of? The last thing I need is to screw up my moms truck.. just because I cleaned the engine :damnit: . You think this'll clear up fully, or you think one or more of the coils are screwed up for good? I hope not. This will be the last time I do that.