Trip meter issue 05

My daughter just bought a 05 TB LS. The dealar was 100 miles away(Per mapquest). We drove the TB home for overnite. When returning the next morning we filled the tank and reset the trip meter. We left the TB at the dealer to fix some issues. Yesterday we drove my 05 Impala to get the TB. Filled Impalla gas tank and reset trip meter at same gas station and took same route. When we got back my daughter filled the TB gas and the trip meter indicated 177.5 miles. My Impalla indicated 202 miles. The dealar probably drove the TB after fixing the wind noise issue plus we drove it 4 miles to evaluate. We don't know exactly how much, but her trip meter should read more than the Impalla. Her gas milage calced out to 14 MPG using the 177 miles. Is there a problem with trip meter accuracy? Would the odometer also be off. How can this happen? Could this be why some people report poor gas milage? Is there some way to fix this?

That is weird. Do the TB and the impala have stock sized tires? First, I'd verify all 4 tires on both vehciles match the door label specs. That's the only thing I could thing of that would effect the ODO, off sized tires:uhoh: . That would effect the speedo as well.

G/luck
Joel

Is there a problem with trip meter accuracy? Would the odometer also be off.

The trip meter, odo, and speedo are all linked (and all will be off with different tire size). An easy sanity check is to borrow a GPS receiver and test all three. The speedo will typically read a few mph higher than actual (they err that way so you can't blame the equipment when you get busted speeding). Even easier for the trip meter is to use freeway mile markers.

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