ok so outa the blue, i was driving my truck home and it started to kinda surge. at first i thought it was a miss in the engine. but i held the pedal steady, and watched the rpms and listened to the motor. it was running smooth. about a mile from my house it started to buck. it felt like i was in a rocking chair. now figuring it was in the drivetrain, and from a suggestion from a friend, i removed the front driveshaft to try to isolate either the front or rear end. so the problem still is there. i jacked up the rear and spun a wheel. i personaly felt it didnt feel smooth. my friend feels it felt fine. has anyone come acrossed this or have any ideas? here are my mods, rear add a leaf, torsion bars cranked. running 17x8's with 1.125" spacers and 285/75/17 dune grapplers. don't think it would matter but i have a body lift also. the rear shaft is tight and the universals seem good. no ticking or movement. to me the rear end looks out a small amount, but was told it is fine because the pins are in the springs. dunno, i am lost. also it is a 99 scab, 4.6 5spd. thanks in advance, bob

 

u may have a coil pack on its way out. i know it may not seem it but when i had one go i coulda swore the truck was gunna fall apart

 

i just changed one on my wifes expedition. i don't have any check engine light on though. should i check the codes? is it possible to pull a code without throwing a light?

 

if it set and the light came on and u didnt notice and it shut off it is.. possible my truck did that to me once no light but i managed to get a code... what i do sumtimes is get on it hard or climb a long hilll and i get the light to go on