Is this a 4.0 motor :
I can't say a simple tune up will resolve this.
I don't know the history of it, and don't have it here.
I'll say that it would be a very good idea regardless if it needs it to correct your problem.
It is frustrating to help when I work in this situation, but rewarding when we have success
Was the fuel pressure checked? What was it?
I would try what I call an air induction service.
I like to use castle hydroblast. You spray it into a vacuum line such as the brake booster line if nothing else is accessible. Full spray for 3 minutes, stall the engine with it or have someone kill it while your spraying. Let it set for a few hours then take for a short drive in low gear, revving the rpms to help break it up. First use Castle cleansrite to clean the throttle bore. Try to get the throttle plates scrubbed good with a brush, while your spraying. Use a rag to wipe the carbon out between brushings. Seafoam is another good product, but smokes a lot.
IF you can't find Castle, here is my rep's email:
A professional fuel injector cleaning may also make a difference.
Saturday, January 6th, 2007 AT 9:38 PM