techometer's mpg gauge question??

[GUERONASTY]

I got a '87 325is...

Okay so took my car in to get rear main seal & rear main seal cover & oil pan's gasket replaced, leaking oil. After I got the car back my MPG gauge was not working properly. It reads 5mpg where I'm on it or barley even at 500rpm on any gear. As soon as I let off gas goes to 40mpg when it should be at no reading at beginning of guage. Everything else works. Anybody was this happen to them or has some advise as far as what's wrong or needs to replaced / adjusted???

[nando]

it's likely a coincidence. SI board batteries could be dying - basically the behaviour you're telling me, the MPG gauge isn't getting any input from the DME at all.

[GUERONASTY]

it's likely a coincidence. SI board batteries could be dying - basically the behaviour you're telling me, the MPG gauge isn't getting any input from the DME at all.

I figured thanks for info!