Cadillac STS

Why does my 99 Cadillac STS miss at idle and on hills if I increase idle speed to 800 RPM with my foot on the brake the idle miss goes away?

User Avatar
Wiki User
September 13, 2011 11:58PM

Obviously this cannot be diagnosed without seeing it but heres a

suggestion to consider. When you put your foot on the brake and

bring up the rpms you are smoothing out the engine. You may have a

bad plug wire that is "moving in the breeze so to speak" the engine

may be vibrating it just enough to come close enough to a ground

that will create a skip. I had a similar problem with a VW years

ago. Going up a steep hill it would skip. At idle it would skip

intermitently. I was looking at it under the hood one night(in the

pitch dark) and caught a glance at the spark jumping over to the

engine from a plug wire intermitently. Changed all the plug wires

and it never happened again. Look for a bad plug wire. If you have

high miles just change them and it will probably cure your


Copyright © 2020 Multiply Media, LLC. All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.