I am new to this forum so hopefully I am posting this problem correctly.

I recently got a used 2001 Century with 252,000 KM. It runs well however recently I noticed an odd problem with auto acceleration. On the highway I noticed that the car would continue to accelerate on its own even though my foot was NOT on gas pedal (just like it was in cruise control mode). The car would continue to accelerate for many miles and did not slow down - in fact it seemed to gradually increase in speed. I would brake to slow down car but after releasing brake the car would again accelerate again on it own. I tried to activate and de-activate cruise control to see if this would correct problem but no effect. After exiting highway I noticed same "auto acceleration" problem occurred at slower city street speeds. When arriving at my destination and puttng car into PARK, I noticed idle was high. I drove car last night and car ran normally and I could not replicate problem. Today the problem came back again. Does anyone have this problem and is there a solution to fix this?

 

The first thing you might try is to go to someone like Autozone and see if there are any codes in the computer. They don't charge for reading codes.
Not always will the service engine soon lite come on when there is a malfunction, but a code could be stored anyway. Let us know what you found.

 

I took car to auto parts store and got them to do an ODB scan and there were no trouble error codes.

So I cleaned the throttle body with throttle body cleaner. I did not remove the throttle body but cleaned as deep as I could. It was pretty black with carbon build up deep inside. I did not have any Mass Air Flow cleaner so for now I did not spray clean the MAF. I'm a bit nervous about cleaning MAF because it is so sesnistive but may clean later if problem occurs again. I checked the throttle cables and from cable that is visible I think the cable looks to be in good shape.

The car is driving well right now so I will continue to monitor and see if problem occurs again.

Question: Until I can resolve or understand this problem I don't want my kids driving this car. So if I simply remove the one fuse for Cruise Control located in the passenger fuse box, will this deactivate just the Cruise Control or by removing this one fuse will other areas of the car functions be affected as well?

 

If you have the owner's manual check in there it will tell you what else the cruise fuse controls if anything. I don't know for sure if the fuse removal will prevent the problem.

 

There would be some carbon build up near the throttle body so have a throttle cleaner and check the IAC also if it is dirty so clean it up .You can take your car to a good mechanic who can sought out all your car problem but take it to some certified mechanic only.

 

I have a similar problen with my 2001 Park ave. But, the issue resolves when I shut off the cruise. The other day I had removed the MAFS and cleaned it with MAF cleaner and spray a few shots into the throttle body with the hose removed. Did not notice any difference at that time. Still idled at bit rough but Put a few hundred miles on the car with no cruise control issues. Not sure yet but I may have cleaned something out that needed cleaning. I too have been advised to check or clean the IAC. But, I dont know what that is??? LOL. : j

 

IAC- Idle Air Control. Seems would be in conjunction with TB butterfly valve; may maintain electronic or cable gas pedal for idle. No idea if still used even, just noticed my LaCrosse has direct fuel injection, when all else fails I manage to read labeling on engine cowling lol.