I have a 2001 f250 with 5.4l v8. My truck was running fine until I sprayed alot of garden hose water underhood on engine about 2 weeks ago. I started my engine about 25 minutes after spraying the water on engine. It was misfiring and still is. So I have replaced all 8 sparkplugs and all 8 boots (coil on plug boots). Still misfiring. I have had no "sevice engine light". But had them run the codes after I unplugged my MAF setting off the Service engien light. There was a code stored that at some point cylinder 3 misfired. What should i try now? I plan on changing the fuel filter, ive cleaned my MAFS. My engine misfires in idle, running rough, and misfires when the engine is on load and it especially misfires/shakes at 1500 rpms in like 3rd gear. Thanks for helping and taking the time!!!! Also should i try the spark plug tester on cylinder 3 and see if the top of the ignition coil boot should be replaced. (the plstic thing that plugs in at the top of the rubber boot and spark plug)???????????

 

The plastic thing at the top of the boot is the coil pack.

An easy diagnostic to do is to switch the #3 coil with one from a different cylinder. If you get the misfire on the cylinder you moved it to, you know that coil is bad. If it stays on cylinder three, the problem is still there, which may be an injector.

 

I think you got water down your #3 spark plug hole. That rubber boot isn't sealing the water out when you hosed down your engine.

Pull the coil and boot off and check. If water is down there, take compressed air and blow it out.

 

Never wash a Triton engine.............never.