Ultra Gauge Runs with Key Off

[hoopty_yo]

I noticed my Ultra Gauge reads .08 GPH with key on engine off. What exactly is it calculating to come up with that number? I've had it drop my average a little if I'm messing with it for too long. Anybody else have this issue? It's a
'99 Saturn SL2.

[Joenavy85]

mine goes blank when i turn it to engine off, if i then turn it back to ignition on it turns back on but shows either "0.00 MPG" or "err"

[hoopty_yo]

I should have put "engine off". A little confusing, but you get the idea.

[Phantom]

Do any other sensors read higher than they should at that time like TPS?

[hoopty_yo]

Nope. TPS @ 0%. Nothing else that I've seen. Just noticed that my avg mpg will drop a tenth or two if I sit too long with the key on. It seems to have dropped to .06 GPH from .08 after I did the mileage calibration.

[SentraSE-R]

It's probably residual voltage bleeding through, specific to your car. Some, for instance, don't close their TPS completely. My wife's Hyundai Elantra keeps something on with the ignition on/engine off, so its avg mpg (as indicated by Scangauge) keeps on declining with ignition on/engine off.