2001 Jimmy not running right

07-25-2010, 11:07 PM
Somebody help me!! Changed the motor last year, now have a 4.3 with 80,000 and ran like top. In Dec the wife wants a new vehicle so this one gets shelved until spring when I finally get around to selling it. Moved the camper in the yard with it Memorial Day weekend, the next week I go to wash it because someone is coming over to check it out and it won't run....at least not run right. It wants to run, but it just chugs, one cylinder at a time. I think it is wet electrical because it is really humid out. Buddy of mine thinks it is not getting gas. Pour gas in the throttle body and it starts up and run good...until that gas is used up. Ok, changed the gas filter (tried blowing though the one just taken off and very hard to blow through it) Put the new one in and the car starts right up and runs like a champ...until the next time I go to start it and I'm back to chug-a-lug. I blow through the old filter again now that it is dried out and blows though with very little resistance. Check the fuel pressure (got a gauge the last time I changed the fuel pump) and it is at 50-55 lbs, so I think it is time for another pump. Just put in another pump and I'm still chug-a-luggin. Check out my video of it trying to run

Anybody got a clue. When I changed the motor, I did put in the fuel injectors from my old motor that had about 20,000 mile on them at that time. Like I say, the thing ran great in Dec, just passed the CT Emissions test that month. I don't think I have thrown a code yet (at least the idiot light isn't lit when I do get it running (I was able to get started and keep it running good when I moved it to the area in my yard where I replaced the pump.)
Another thing, while the tank was down and I was cleaning it out, I found this at the bottom of the tank (see photos). Anybody know what this is??

07-26-2010, 12:24 AM
So we know its running lean, what happens if you unplug the MAF sensor?

If your adding fuel and it smooths out and you replaced the pump the only thing left is the CPI unit. I'd like to see a couple pieces of data on the scan tool before I made that call.

07-27-2010, 07:15 AM
I'll do the MAF unplug. Don't have a scan tool, hoping someone has had their's run like this to give me a clue what fixed their's.

Add your comment to this topic!