i have a 98 expedition 5.4 a/t. with a bad engine miss. at koeo it's showing ign. coil pri/sec circuit fault, cyl 4 misfire, and obd2 checks incomplete. at koer it's showing downstream sensors not tested, tcs out of self test range, and cyl head temp sensor out of range. if anyone has an idea of where to start i'd love to hear it. thanks

 

mileage? ever been tuned up? and was dielectric grease used? its most likely that coil. you can get a full set of 8 off ebay for around 80 bucks. just type in dg508 and look for global or uneek. i'd do plugs if you change all the coils, motorcraft plugs only

 

beats me. i just bought this truck and haven't got it towed to my house yet.i've always had f-150's so the expedition was my first choice for an suv but i've never had any engine trouble with any of the ones i've had in the past. i'm a professional body man (17 years) and i do all the mechanic and suspension work where i work but my diagnostic skills are lacking. i really appreciate the input! the guy i bought this from wouldn't know a intake from a vacuum cleaner so i'm a little worried about the maintenance. thank you!