Greetings I am new to this...Looking at purchasing a 2003 Pontiac Bonneville 160,000 miles. Today I drove it and noted that the "check gauges" light was on and the fuel gauge was acting strange 1st said it was full, then I turned off engine then it said Empty. Oil gauge showed 120??? What are the potential issues? 2800 for this vehicle. Thoughts??? very well maintained....

Welcome. We bought our daughter a 2002 Bonneville 2years ago. We have the same issue with the fuel gauge. It has never been accurate as well as the speedometer. The electrical system is q little wonky when it comes to the windows. Other than those issues, no mechanical problems. It also is immaculate. My husband did some research on them and found that these are common with some of the Bonneville'*. We couldn't have picked a better car for her. It also had just over 160,000 miles on it. Good luck to you.

Welcome to the forum

oil pressure sensor is bad. this happens on almost all cars with the 3800. its an easy 2 minute job you can tackle while changing the oil.

the gas gauge is a bad fuel level sensor. you can ignore it and use the driver info center and look at the "fuel used" option.


seems like a decent car welcome to the forum!!

Welcome to the Forum Pam !
Please let us know if you purchase the 03 Bonneville!

Likely going to need a lower intake manifold gasket; unless already replaced. You don't mention the condition. I would be wanting to pay under 2k for a 2003 Bonneville that needs some work.

I current owner took the car to the oil change place and they found the sensor was bad - it was replaced and an additional $75.00 later. I am going to take another look at it tomorrow. My gut tells me that it is a good car and the engine is a good performer. Thank you everyone for the comments. It has helped me out immensely!

Whenever you turn off the engine the cluster partially shuts down and returns all gauges to start position. So if you turn the key from On to Acc, the fuel gauge SHOULD go to empty.

Good to know...I will have to look closer at this. I could have done that as I was at the car wash and turned off the engine....Dumb mr. Thank you all for your insight.