Hi my 2001 f150 with a 5.4 has a misfire on cylinder 1 I had have replaced the coils and plugs, the truck ran fine for one day then started to misfire again. I have signal to the coil and injector , and swapping coils and injectors dosent move the misfire. The oil looks good, no coolant in it and no oil in the coolant. I haven't checked the compression yet but is there anything else I should check for to figure out the problem?

 

I'd pull the plug and check for coolant on top of the cylinder.