engine "surge'hesitation problem

Since Ventures and Montanas are similar vehicles, I am posting this question here as well as in the Trans Sport section.

My 98 Trans Sport Montana, 3.4L, has developed a problem.

When driving along, it intermittantly "surges" or "hesitates" , I don't know how to describe it really. It is like it is loosing all power but then it drives proper again.

No dash lights come on, no service engine light. I don't notice the tach reving high or falling off.

I am suspecting the fuel system. I had the fuel filter replaced and the pump tested. Mechanic said it had good pressure. But since it is intermittant maybe the pump is only running full pressure most but not all the time. Don't know if engine need makes it pump more or should always be one pressure..

It seems to have the problem when the vehicle is under load...like climbing a hill or wanting to get up to speed. If it is babied, I don't recall it happening.

To me it is similar to a chain saw problem...you get a piece of saw dust in the tank, and occasionally it blocks the fuel line by the piece getting in the flow, but then you shake it and it gets out of the way and then runs well again until that piece gets stuck in the line again. Does that make sense?

When the fuel filter was replaced, the mechanic said it was really plugged up, he could hardly blow through it
Could there be crap in the tank...how would I check?

Any constructive advice would be appreciated.

if the filter was plugged bad there may be rubbish in the tank. the tank will have to be removed and the fuel pump removed to look inside. and yes to your question about more power equals more fuel needed. in the case of the injectors being open longer to deliver more fuel, this would cause a pressure drop across the injectors. have your mech check the fuel pressure while he/she drives it around under load etc and note the pressures. If memoery serves 40 to 47 lbs is yur specs.

also have the mechanic look at the pulse dampner. is in line with the fuel pump and injectors GM usually puts it with the fuel pump assembly.

It could also be a problem with your emissions or exhaust system. A clogged cat can cause a lack of power under a load but runs fairly smoothly at an idle. Also a faulty EGR valve doesn't always trigger a DTC but may be dumping too much exhaust back into the system (or not enough).

It's been a while since I posted my problem.

I had it checked out and a couple of things came back.

The mechanic found that one of the battery cable was almost off of the bat. So it was causing some intermittent problems.
But after that it still had some surgeing.

A code was found and it related to the Transmission. I took it to a transmission shop and they said it indicated a bad sensor on the trans. I have no specifics on what the sensor is or does.

After that was replaced, it was a hot day, near 100 degrees and I drove more than my typical 9 mile to work trip, and it had a slight surge/jerk thing a couple of times, and along with at a whine or whistle noise. Was hard to tell.

But it only did it a couple of times after the longer drive in the heat. Later the same day, going back home for the short drive it made no noise aor had any proble, and none since.

The weather is getting cooler now and again, I am not driving a long distance.

So that is the condition for now.


All may be fixed...not sure, but no problem is showing.

If this only happens when driving and in overdrive, it could be that the torque converter is slipping. The fix is to cange some soleniods and a seal inside the transmission. I can not remember which seal and solenoids.