New guy here, appreciate y'alls help! 2000 Jimmy 4x4, 185k.

This problem suddenly appeared a couple weeks ago. When pulling away from a stop, or coming to a stop, the truck bucks and stumbles. Not every time, but about half the time or more. Seems a little worse coming to a stop, it will buck and act like it wants to knock off, but only has once. No CEL. (It did come on for a few minutes once, that is all.) Seems to have a slight occasional miss when driving, but much less noticeable. The nature of the miss seems to be on/off, felt like an ignition problem to me. Over these two weeks it has gotten progressively worse, but not dramatically so.

Well, I've had it since 150k, never tuned it up, so I replaced plugs/wires/cap/rotor/air filter today. Old plugs were pretty, light gray, clean. No change in my problem, grrrr.

The thing runs strong thru the gears at WOT. That seems to indicate that fuel pump or filter is OK? Any ideas?

 

Anybody?

I did search the forums before I posted (I'm not a forum virgin, just this forum). I saw a couple things about cleaning the MAF or the EGR. Would that help?

I saw a couple other things about the throttle position sensor- I don't think that would cause the sharp cutting out that I'm experiencing. Like I said, it really feels like an ignition thing. But I've replaced a lot of that... would a failing coil do this?

One other thing- this seemed to appear right after I got a tank of gas. But that tank ran out yesterday, and I put half a tank of mid-grade in it. Situation unchanged, it might still be getting slowly worse.

 

check ur fuel pressure. and a fuel leak down test.

 

I had similar symptoms. It was a worn drive gear in the distributor. When I pulled the cap I noticed some rotor pieces broken off. I could wiggle it around at least an 1/8".

 

Definitly clean your MAF and your EGR. I would also replace your fuel filter.

 

You will not believe what the problem was...

So, I had cleaned the MAF and the EGR to no effect, hadn't had much more time to mess with it until today. Decided fuel filter was next, stuck my head under the thing to verify where it was and what was involved in changing it.

Then I looked around a bit. Noticed there was wires in that plastic flexible conduit stuff resting on my front driveshaft in two places- odd. Had been for a while, obviously, because it had worn through the conduit and worn on the wires as well. Moved the wires, drove the truck- it ran like a Swiss watch!!

Not sure what these wires are connected to, but clearly this was the problem! Ran great all day. I'll get under there in the morning and patch up the wires and conduit, and support it up off the driveshaft.

I just KNEW it was electrical in nature! Jimmy is back in the saddle!!!

Thanks to all...