Power loss on 2000 Pontiac Montana


I have a problem with our 2000 Pontiac Montana van that has stumped my GM-certified mechanics. We have had sudden power losses while driving. The van goes along at 2000 rpms and suddenly loses power. Because my foot is still on the gas, the rpms shoot up to 4000-5000, but no real acceleration. I really have to step on it to get any power, so I just coast along, and after about 10 to 20 sometimes 30 seconds power returns as normal. This can happen two or three times in a 30-mile trip. No warning lights have ever come on and the mechanics say no codes can be detected. We have flushed the fuel line filter and given gas treatments, etc. I will say, this problem has decreased significantly since it got cold. The mechanic says its either a fuel or an electrical problem and wants it to get worse so it will really be apparent to fix. But this has been going on for months, and I can’t stand it. It also poses a highway hazard in heavy traffic. Please help.

I would guess it is an automatic transmission problem (start by checking the fluid: Level and Condition) or if a manual, the clutch.


I think Joseph is on the right track.

You said this problem has DEcreased since the cold weather started.

That MAY be due to the tranny fluid staying more gel-like longer until the fluid gets hot.

I’m guessing, but a faulty VSS (Vehicle Speed Sensor) may have some input here. (maybe not)

Lets see if Transman comes around and helps you out.


You don’t mention anyone being concerned this problem could be a serious transmission issue,can you explain this?


oldschool and Joseph are on the right track, IMHO. If your RPMs are suddenly shooting up by 2-3k, but you feel as if there is no power, that is almost surely a transmission problem.

If your GM-certified mechanics are stumped by these symptoms, then I am not very impressed with them. Your RPMs increase, yet you have no acceleration ability, and those mechanics think that it is a fuel problem? It is possible that this could be a strange electrical/electronic glitch, but a fuel problem? Nope!

Ask for recommendations from friends, neighbors, relatives, and co-workers for an independent transmission shop in your area. DO NOT go to AAMCO, Lee Myles, Cottman, or any other chain unless you want overpriced, substandard repair work.

I would be very surprised if this turned out to be something other than a transmission problem.