I have a 1993 deville 4.9 liter. I recently had problems with ses light coming on and it pointed to the ISC Motor. I replaced the motor and did a Throttle Body Cleaning and to follow a idle relearn.

Now the car idles fine, but when it first starts its about 1000rpms and then goes to normal idle. If I am driving down the road it seems like the car is on cruise control cause it mantains its speed on its own.

If I am on the highway and get off the ramp its idle is high and when i get a light its high but then returns to normal. I am at a lost because I dont know what else to check. I read on another post if the TP Sensor is not set right it would cause a trouble code. Any thoughts, i know BBoB is the man in this dept .

Thanks for your help in advance

Anybody have a take on this?

Did you replace the part with an after market unit or the original part from the dealer???? If it is an aftermarket part then my guess is that the part is just that way.

The other thing I could think of is if the cruse control is not properly adjusted.

Good luck.

Have the throttle body and plates been cleaned?

its an aftermarket part from autozone, but from what i have read in here, people have used them before and havent had any problems. I did a complete throttle body cleaning.. it actually runs pretty smooth, but if u rev the gas in park its takes some time for it to return to normal.

I have had the same problem on my 94' Eldorado. I changed the idle ajusting motor (don't know if this is the right word - I'm German) and everything was ok. This ajusting motor had been completly eaten from inside (all plastic)

When you cleaned the throttle body, did have had a look on the gaskets? Maybee your motor gets wrong air from there,
Tom

Ok guys need your input on this one. I cleaned the the throttle body again and this time clean the EGR tubes they were compleltly clogged after that i did and i idle relearn. The car now seems fine idling but still sticks if you rev it high and or are slowing down at a light?

What else could be causing this.. throtte position sensor maybe?

the car is running great but driving me nuts because its like racing when you hit the gas. I checked all these threads but am coming up with the same things i have done.:banghead:

Any help would be appreciated

How are the throttle return springs on the throttle body? Any binding when you opertate the linkage by hand from under the hood? Any binding in the throttle cable? Fraying on the cable? Should be some slack in the cruise control cable.
Just a couple of shots in the dark.
FWIW
YMMV