Alright I have two issues.
First is my mom's 2004 BMW 525. When accelerating, the RPMs move up and down very inconsistently. Overall, the car seems to accelerate fine, but the car is slightly jerky due to the quick and small changes in RPMs. It's acting like you're quickly pushing and letting off of the gas pedal, but in fact you're holding it steady. I've only driven it around town on very short trips so I'm not sure if it gets better as the car warms up. Perhaps a faulty or dirty mass air flow sensor?
The next problem I'm having is with my 2003 Nissan Pathfinder. The brakes make a hi