I recently had about $800 of work done to my 02 Monte Carlo. Now the change oil light comes on whenever I start the car up and goes off after a minute. While driving the oil pressure gauge will decrease when the brakes are applied and increase when the accelerator is applied. I been looking around for help but can't find anything. The only thing I can find is a bunch of people thinking that this is normal. It's not. I've been driving this car for a year now and it's never did this before. Any ideas (except for people saying it's normal) would help here. Thanks.