Buick Century Acceleration Problem!
 

Can anyone advise me about my 2002 Buick Century Ltd? Yesterday the car accelerated (without cruise control on or with my pressing the gas pedal down) while going up a steep interstate hill. Only hard braking and ultimately shifting the car into park (as I got it to slow down by braking) got it to stop. The tow truck operator checked the throttle cables and said they were working properly. He disconnected the cruise control and test drove it. (I am amazed that I did not tear out the transmission.) The car was my mother's and I have had it for almost 8 years and kept it well-maintained. I am afraid to drive it now. Thx.

Should start your own thread.....sure you don't have a floor mat problem?

This is my first time here so I don't know how to start my own thread--sorry! And, no, it is not the floor mat. Wish it were so simple. I would not have bothered to seek help if that were it.

Debby Welcome to the forum! No Problem, I moved your posts into a new thread for you.
This should assist you with your acceleration problem specific to your 2002 Buick Century.
Starting your own thread is easy....just look for "New Thread" and add a title and continue your post in box below.

Re Your problem of accelerating up hill:
The car should be checked out to include the IAC (Intake Air control- controls idle) and performing properly.
Often removing the IAC and cleaning the pintle/ spring end, with throttle body cleaner, can restore to working condition again, otherwise it may need replacement.
Also the throttle plate needs to be clean, free of carbon that can get stuff a bit sticky, you want the throttle plate to move open/closed freely and no binding anywhere in between.
And even though the tow truck man had a look at the cables, they also should be checked for correct movement, around the throttle linkage area, to ensure they are returning correctly and also not sticking.

I hope this may help Debby.

couple be throttle position sensor as well.

https://www.gmforum.com/trouble-shoo...sensor-279319/

Would a problem with the throttle position sensor occur without the check engine message? Thx.

Debby, A failing TPS can trigger an MIL or (Check Engine light) but not always.

Thank you again! I would like to keep driving "Bob", but have to know that I am safe. I have jotted down your recommendations and, with this knowledge, I feel better prepared to make sure Bob is thoroughly checked and repaired. The mechanic who breathed life back into Bob 3 years ago has moved to another city which would involve a very lengthy tow so I want to know what I am talking about with a mechanic I am less familiar with. Thank you again!

You are welcome Debby and I hope you get your Century back into trustworthy shape.
One further mention, is we recommend the use of Delco replacement parts only when it comes to the IAC and TPS.
There have been problems with "other" brands so for reliability, it worth the extra $ to use Delco.

Art, thank you for the further advice. I will certainly request Delco. I am having Bob towed to the dealership this Thursday morning. I don't want to sound like a jerk, but I insisted that the mechanic review my list of possible problems/solutions (from the notes I have taken via this thread). The service adviser told me that I had to tell him, not the mechanic. This is so unlike the mechanic who worked on Bob previously. That mechanic would show me the problems and discuss them so that I could understand what needed to be done. Unfortunately, he is not there anymore. I am worried that a thorough diagnostic (as outlined on this thread) of the throttle position sensor may not be done. It seems crazy, but I had an acceleration problem with my dad's 1982 Scottsdale pickup truck and it was never resolved by a couple different dealerships as well as non-dealership garages.

Thank you again and I will post what happens on Thursday.

Debby