My wifes SUV is a 2000 GMC Jimmy. It has over 100,000 miles on it. When it is started it sounds fine. When you put it into gear (it is an automatic) and press the gas it barely moves. You put your foot to the floor and it does not move much. After about 30 seconds this disappears and it works fine. We have sprayed carb cleaner on the throttle cable and it helped a little and we also put a gas additive system cleaner and that also helps a little too. Outside tempature does not seem to affect it. Any ideas?
When you put your foot to the floor, does the engine rev up?
No…it sounds like it about to stall but does not.
You may have a dirty IAC (Idle Air Control valve).
This could be a headache and it seems to be an electronic control problem. Good luck finding the exact cause.
It might be a defective thermostatic fan clutch. If the fan clutch is locked up when cold it can put enough of a load on the engine to cause the problem you are having.
When the engine is cold try spinning the fan, it should spin freely. If it doesn’t spin then it needs to be replaced.
Of course I’m assuming it has a fan clutch, if it has a electric fan then it isn’t the problem but it gives you something to check.