theres a vibration on 2001 Dodge Ram 1500

between 40mph and 55mph there's a vibration like a wheel is out of balance when the o/d is on but goes away when o/d is turned off what would cause this

by in Mooresboro, NC on May 28, 2013
2 answers 4 comments
ANSWER by , May 28, 2013
Check engine light on or flashing? Vibration or a fast jerking like a misfire? Misfire more likely to show up in OD than other gears, more load on engine/ignition system.
COMMENT by , May 29, 2013
there's a misfire on #1 and #8,changed the cap and rotor[yesterday] and put new plugs and wires on about 6 months ago but still have misfire on #8.could bad cap cause wire or plug to go bad?
COMMENT by , May 29, 2013
Wires crossed? V8? Cause firing order is 1-8-4-3-6-5-7-2. 1&8 can easily be crossed. Try swaping wires between 7&8 to see if misfire follows wire. 7 is rear plug on left, 8 is rear plug on right. If misfire does change with wire replace wires, if not then check plug, compression and injector pulse or have this checked!
COMMENT by , May 29, 2013
put new wires and plugs in but the vibration is still there between 40mph and55mph.now also when I gas on it the check engine light blinks but goes off.it's a 2001 5.2/318 v8 with 100250 miles next thing is a compression test.what should the compression be?
ANSWER by , July 04, 2015
bad vibration between 40 - 50 but if i take off fast like paddle to the floor no vibration 1997 dodge ram 1500
COMMENT by , July 04, 2015
Had the same problem in my 2001 ram 1500.Found that new plugs,cap rotor,and wires took care of the problem and its been running fine now for about 2 years.A misfire caused the problem