95 4wd rough start if start and misfire and sputtering like it is running 3 cylinders

[gmc95]

I had been driving for 2 hours stopped truck. THe next morning the truck started fine and I drove about 1.5 miles and I felt the first hesitation and then another. I drove another miles and it started to get worse. When I take my foot off the gas the RPM would rev high and low and go dead.
I recently gave it a tune up. I changed the spark plugs, oil, air filter, fuel filter. The fuel pump was replaced about 6,000 miles ago.

I have checked the fuel pressure (it is 55lbs.), fuel injectors look good, timing is fine, EGR is fine, checked for vaccum leak, fuel pump, and rechecked spark plugs and fuel filter. I don't know what it could be...Can anyone think of anything else or ran into a similar problem before.

Thanks.

[XtremeXP]

If the egr is fine it is probably the cpi unit leaking. Just do a search on the forum for cpi and you'll find alot of info on it. Mine was doing the same thing and thats what it was. Cost me just under 200.00 I beleive doing it myself. It was actually pretty easy to do.

Do this. Take off the vortec cover on top of the intake and then remove the round valve I think it has two torx screws. Then shine a flashlight down the hole. If it's clean on either side your cpi or fuel lines are leaking.

This is a pic of the booger http://www.rockauto.com/ref/SMP/SMPD...html?FJ226.jpg

[troubles789]

Check out my last post on this page. 93 egr problems. ended up the cpi. Less then a hour to replace. Bought ebay route for half price. $153 v/s $300 total at advance auto. But you give up the year warranty.