Engine revving too high?

ROSELLIA

MEMBER
1994 CADILLAC DEVILLE
4.9L
V8
2WD
AUTOMATIC
98,872 MILES

Recently I had a new muffler installed that gave it a deeper tone but wasn't overly too loud. I've noticed now that if I start the car, it feels like it had more power to it and I can feel it pulling more. A minute or two later it calms down. I also noticed today as I was pulling into work. It was doing that same thing but when I put it in park it was still doing this and then after a minute calmed down.

Tuesday, June 13th, 2023 AT 4:32 AM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
54,137 POSTS

Usually this happens when the idle speed control motor gets weak and cannot perform as it should by it could be a vacuum leak as well, also we should run the codes.

Here is a guide to help, use it only when the engine is cold:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

and

https://www.2carpros.com/articles/engine-idles-too-high

Here is how to run the codes and I have included how to change out the Idle speed control motor as well in case a code comes up for it. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

Images (Click to make bigger)