Strange RPMs while stopping

dwd1985 · #1 02-28-2006, 12:57 PM

I just adjusted my TPS to EXACTLY .5 Volts. I thought this would fix one of my problems, but it didnt. As im coming to a stop, when im at around around 1000 RPMs, my RPM's will suddenly increase slightly (like by about 50), and the car will take a slight lurch forward, even though my foot is on the brake. It could possibly be while it is downshifting into first gear. It happens everytime I am stopping. But all of my other shifts are fine, including the upshift from first to second, so im pretty sure that it isnt a tranny issue (but I could be wrong). A possibly related problem is that when I am accelerating at low speeds, and then take my foot off of the gas, my RPMs will drop VERY quickly, and then suddenly come back up again alittle. However, driveability isnt affected at this time, its like you cant even feel it. Any ideas? I thought this was all TPS related, but I geuss not...

intelisevil · #2 02-28-2006, 09:23 PM

Is your AC/Defrost on? If so, the rpms will increase at idle, maybe that's what is happening. As the engine slows down to idle speed, the circuit kicks in to increase the speed.

This morning I was sitting at a stop light in Drive with my foot on the brake. I turned on the Defrost and the increase in idle (about 100 rpms) was enough to overcome the slight pressure I had on the brake pedal, I actually moved forward for a moment until I pushed on the brake a little harder. Fortunately, I was the first car in line, after a twelve hour graveyard shift my reactions aren't always the fastest . . .

dwd1985 · #3 03-01-2006, 12:08 PM

Quote:

Originally Posted by intelisevil

Is your AC/Defrost on? If so, the rpms will increase at idle, maybe that's what is happening. As the engine slows down to idle speed, the circuit kicks in to increase the speed.

This morning I was sitting at a stop light in Drive with my foot on the brake. I turned on the Defrost and the increase in idle (about 100 rpms) was enough to overcome the slight pressure I had on the brake pedal, I actually moved forward for a moment until I pushed on the brake a little harder. Fortunately, I was the first car in line, after a twelve hour graveyard shift my reactions aren't always the fastest . . .

It happens regardless of whether the AC/Defrost is on or not. Does anyone know what this could be? I have been troubleshooting this problem for some time now...

Earthworm · #4 03-01-2006, 01:38 PM

Does it only do this once per stop? Perhaps the AWD is binding? Try inserting the FWD fuse to see it the problem goes away.

dwd1985 · #5 03-01-2006, 03:23 PM

I just put in the FWD fuse, and it didnt change anything, so I geuss it isnt AWD binding. Any other ideas?

Earthworm · #6 03-01-2006, 03:30 PM

The FWD light came on right?

At what speed does this happen?
Have you ever verified the TPS is properly adjusted?
Will this happen with the shifter in different positions? (1,2,3,D)