90 sedan deville idles REALLY fast

[avillajonathon]

I have a couple of questions regarding my 1990 Cadillac sedan Deville.

#1: when i go to start it any morning,(cold or hot) it takes forever for it to start

#2: when it gets started, it idles really really fast until i tap the pedal.

#3: when i go to take off, even if i have been driving it all day it will almost die, and when i push on the gas it like surges until you let off the pedal a lil bit then will accelerate fine. same thing if i am already driving down the road and push the gas to go into passing gear.

so if someone could please help me with these issues i would really appreciate it thanks!

[adallak]

I have a couple of questions regarding my 1990 Cadillac sedan Deville.

#1: when i go to start it any morning,(cold or hot) it takes forever for it to start

#2: when it gets started, it idles really really fast until i tap the pedal.

#3: when i go to take off, even if i have been driving it all day it will almost die, and when i push on the gas it like surges until you let off the pedal a lil bit then will accelerate fine. same thing if i am already driving down the road and push the gas to go into passing gear.

so if someone could please help me with these issues i would really appreciate it thanks!

Welcome to caddyinfo.com!

Make sure the cable which is connected to the throttle body lever moves freely. Clean the throttle body and the back sides of the blades with carb cleaner.

If you have an Ohmmeter, measure the resistance of the TPS (throttle position sensor attached to the throttle body) while you are moving the lever up and down. There should be no jumps in the readings.

Idle speed control motors are know to fail as well, but first check out the stuff mentioned above.

[KHE]

Sounds like an issue with the idle speed control (ISC). There is a ton of information in the archives on that.

[avillajonathon]

thanks pple i will check everything first thing in the morning

[adallak]

thanks pple i will check everything first thing in the morning

Your Cadillac is equipped with on-board diagnostics so you do not need to attach any OBDI scanner to read codes. Just depress WARMER and OFF buttons simultaneously for a few seconds and then write down any trouble codes your DIC (driver info center) may show. Turn the ignition OFF after you are done.

The ISC motor is a black box with a plunger which extends and retracts and changes the angle of the throttle lever. If ISC motor makes unusually loud noises, it is probably bad. I went through three ISC motors in nine years on my 4.9 liter which is very similar to 4.5 engine. If it is the case, we will tell you how to install and adjust a new one.