When my Jimmy got messed up, I moved the ScanGauge out of it to my fiancee's '97 Riviera. Changed the engine size (4.3 L to 3.8 L) while running, and then did the "calibration" routine at the first 2 fill-ups.
By dividing miles travelled by fuel added to fill it, it's been getting in the 24-25 MPG range in mixed driving. But the ScanGauge will go from readings that "look reasonable" - in that range, accounting for instantaneous conditions, to "totally crazy". By that, I mean, it'll show 240 to 303 MPG "current", and as I drive, the "tank" reading will keep climbing like it's trying to catch up to the new readings. Then I'll start it the next day and it'll look like it's giving me "correct" readings again - until - the crazy high readings start again. Any ideas what could cause this, or anyone else have similar problems? The ScanGuage was bought in late October/early November, as I recall.
I don't know if it matters, but the "check engine light" is on, and the code is P0102, which appears to be "MAF". I tried to clean the MAF sensor, but the light soon came back on after "clearing the code" with the ScanGauge. Would this have anything to do with it? I wouldn't think so, but????
Sorry if there's already a thread on this - I only looked at the first 3 or 4 pages of this catagory. Thanx...