Car Sometines Surges When Letting Off The Break From A Dead Stop?

Sheekamoo · August 23, 2010

I recently purchased an 97 ES300 and noticed a strange behavior. I've put roughly 250 miles on the car and this has only happened 3 times. When I come to a full stop, 3 times now the car has lurched forward when I let off the brakes. It's not too bad... just a slight move forward. It's mostly felt in the car more then the car actually jumping forward. It feels as if the engine/tran has built up some energy and when the breaks are released that energy is allowed to release as well. I can't reproduce it as it has only happened 3 times and it seems like a fluke occurrence. I've tried braking very heard vs. braking very soft... didn't make a difference.

I'm just trying to come up with possible causes. I'm thinking maybe a worn motor mount or possibly worn transmission mount?

George_Jetson · August 23, 2010

Worn mounts are one thing to look at, how is your idle speed? Is it stable?

Sheekamoo · August 26, 2010

Worn mounts are one thing to look at, how is your idle speed? Is it stable?

I just had the timing belt replaced and they went ahead and did the Bone mount since it was really warn. I'll wait and see if it happens again though.

The idle is very smooth. Once warmed up, it stays at 750 RPM's, and doesn't fluctuate when the A/C is on or off. My mechanic said it could be due to the A/C turning on though. As in, I stop with the A/C off, then start with the A/C turning on and that could cause the surge. I'll have to pay more attention to my A/C and see if that's the cause of this issue. Since it has only happened about 3 times total, it may very well be due to the A/C.