Just put flows on and gas gauge dropped?

I just had Flowmasters installed on my car not even an hour ago and on my way back home i notcied my gas gauge dropped dramatically. I had a half tank and it went to almost empty then back to where it was. Any ideas what could have caused this? I have never had this happen before and nor was I on a hill.

weird. perhaps it was invisible gas syndrome?

Ok ive noticed it is every tim i rev my engine up. I think the resonance may be shaking something loose electronically. Does this sound more logical?

No, the float sits in the gas tank and rises with the level of fuel. The muffler has nothing to do with it. Put gas in and see what happens.

the muffler shop guys prob took it for a spin :D

No the guys didnt take it for a spin considering i was there the whole time and I put gas in the car and had it at a half tank and every time it is revved up the gas gauge goes down then goes back up. Therer is gas in the tank its just when its revved it messes with the fuel gauge.

Check your wiring at the tank.