Just bought a 2001, 2wd with 5.9. Has 77,000 miles on it. At idle I can feel quick vibrations through the front tires and can see the tensioner move with the vibrations. Did compression check and got 185psi except #6 was 175. Autolite plugs in it were clean as a whistle. I replaced the cap and rotor so far. It has autolite plug wires by PO. Didn't really notice it at first because of loud exhaust setup. Any ideas? thanks

 

Light misfire, or motor mounts I what I'd be looking at.


But what do I know....

 

could be any of a number of things..... injectors, crank or cam sensor, loose connections at injectors, etc...... Check the easy stuff first.

 

It feels like a light misfire, kind of a stumble but no hesitation. It also has a jumpy motion only when in gear at idle speed. Same two issues my old red 99 had and never did get those figured out before she broke a valve spring and lodged exhaust valve in the head. That's a really bad misfire now! Crazy curse.

 

are the plug wires routed correctly? I installed new everything in my truck, i followed this and it made a huge difference.

http://www.ramforumz.com/showthread.php?t=46269

 

Yes. Spent plenty of time doing that. Going back to stock exhaust this week end. Not that has anything to do with the vibration at idle.
But at least I will be able to hear the engine. And getting rid of the hot air intake,the way it's set up now. Was thinking of running it for just a minute or two with out the serp belt on to eliminate the fan and accessories? Still has autolite wires. Misted them in the dark last nite, no glowing or arcs.

 

New/old truck is going to the shop friday morning for diagnostics. I think something is off balance. The vibration from motor is constant sitting at stop lights at idle, can feel it throughout the whole front end of the truck. Tensioner pully is moving with vibrations. Every second it does like two bigger jerks, 1/8 to 3/16in. Would you call this normal? any feed back appreciated, thanks.

 

Tensioner shouldn't be moving. Checked your other pulleys and your harmonic balancer?

 

Yes, checked all pulley accessories with tension off belt and everything seems solid. Looks like the fan clutch may have been replaced by PO. Claw marks on the big fan nut. Maybe I should go to different shop. They looked at it briefly today and didn't think that much tensioner movement was any big deal. Ya know these 360's do run a little rough was their comment. It does seem to smooth out upon accelerating.Thanks dude.
Put exhaust back to stock and vacuum reading went from a steady 17 to a steady 18.

 

+1 on finding a different shop. The tensioner on mine moves a tad, but nothing much.