1991 V6 4-runner, poor gas mileage

[DTS]

I'am getting only 12-13 MPG. New timeing belt, new spark plugs, cap and rotor, engine runs great, no fuel leaks. Dealer put scan tool on and no codes.

Is the temp sender that gives info to the ECM, the same sender that give the info to the gauge on ther dash?

My gauge will read cold if I turn on the heater/AC blower. It seems like there is a ground problem somewhere.

What could cause such bad MPG? Any help would be great

[David_T (MO)]

Sounds like the thermostat isn't shuting completly and that's not allowing the engine to reach operating temp when you're out on the road.

I had that problem with another car and took three years to find the probelm as it would always warmup just fine sitting in garage with all the testers on it, but out on the road it had problems. It was the heater running cold one below-zero night driving through Canada that gave me the final clue. Stuck some cardboard in the radiator to warm up the heater and, PRESTO, the car started running great too.