I have a 99 4x4 Dakota with a 3.9 and I can't find a solution for this problem. I put a new motor in it and had to have the fuel sync reset and other than an exhaust leak is fine....until a few hours ago. I came home from work, and tried to leave about 10 minutes later but as soon as I pull in the street, it chugs and acts like its not getting any fuel. I checked fuel pressure and its between 45 and 50 lbs, no check engine light and no codes at all. I haven't had problem since I picked it up from getting the fuel sync set....I'm at a loss. I don't have money to throw parts at it and hope, I just need some opinions. Thanks for your help.

 

Start with the basics, fuel, air, and spark. You have fuel pressure, 45 pounds is a little low, but you're close. Could you have gotten some bum fuel?

We know you have air but how about a major vacuum leak? Check around all the lines, it wouldn't be unusual to have one fail.

Spark, how's the cap, plug, rotor, wires? Did any of them rub on an exhaust manifold or anything?

 

How is your catalytic converter? A bad O2 sensor can make it run like that, too.

 

I'll check for a vacuum leak. But I believe I checked and didn't find anything leaking. The plugs, wires, cap and rotor are all new and spark is good. I was expecting stronger, but it runs fine most of the time. The exhaust leak is pretty bad though. Its from the manifold to the block on the rear cylinder on the driver side that I haven't got to fixing yet. Could an exhaust leak cause these issues?

I don't have a cat and as far as I know the o2 sensors are good. Is there a way I could test it rather than buying a new one?