< JAWS

got a 97 F150 4X4 with a 5.4L... problem is it shakes really bad between 40ish and 50ish... i was told its a coil going bad and that I needed to wait for the CEL light to come on to find out which one it was. I already have the new coil, any way to find out which one to change without goin to autozone, or is there another problem? truck is lifted 6" with a 3" body lift... could it be a drive shaft problem? any help is appreciated.

05 super

any mud on inside of rims? wheel alignment done? wheels balanced? was driveshaft disassembled and put back together with the u-joints out of phase? driveshaft dented? driveshaft balanced? rim bent? i know i'm bored. lol, did this problem happen right after the lift and tires were installed? it could be an electrical problem too, like you said.

< JAWS

see... ive had the truck for almost a month now, and when I test drove it, the truck drove fine... but then about a week after i got it, it started doing this... I was told it was notorious for it so thats what led me away from thinking it was a driveshaft or tire problem...

kdr358

My uncle has a 2000 super crew with 133,000 on it and he said 2 coils went on him he said after about a week his CEL came on. but i dont know if you have to wait but its worth a shot trying to get the codes pulled.

dawggtired

I had the same vibration at 2000-2500 RPM. That will be about 50 MPH. After spending close to two months trying to figure things out I lost my drive shaft. At sixty miles per hour that causes a lot of damage. Pulling your drive shaft and checking the u-joints will probably be good insurance. Good luck.

TUROCK150

Had same issue. Corrected itself when I inflated the tires proper. Hope this helps.