Hi there!

I have a 2008 Mini Cooper S who has been acting weird lately. First off, I have replaced both fuel pumps due to having difficulties maintaining a stable speed on acceleration, receiving “rubber banding” and weird noises. After that, I have had the oil changed and spark plugs replaced, MAF replaced and brake rotors replaced (we got the car off of someone and we were replacing everything to make sure it ran smoothly because it had bad brakes and the fuel pump was giving problems). However after all of this, I am having an issue with my gas meter. Two days ago I had filled up my tank, drove about 68 miles, got home, left the car alone for the night. It wasn’t until next morning that my gas meter suddenly dropped, claiming I had 59 miles left until I was left on empty. I drove another 20 miles with my gas meter being stuck on 59 miles and then shooting to zero as soon as I reached my school. From there, I took it to a gas station, put $5 in the tank to see if I was seriously out of gas (which seemed quite impossible to me because the computer isn’t telling me how much I actually have) and it then said “————“ from which I understand is that I am using my reserve fuel. It wasn’t until I was half way home that my mile counter shot back up to 50, 80, then 90. Today I drove 4 miles and it shot up to 120 before reaching 59 again. My Mini had 120,000+ miles on it. What could be wrong with my Cooper?

 

There is a fuel sending unit that's part of the pump. It's possible that during installation it may have been compromised and is sending bad signals to your gas gauge.