My friend really likes ugly old cars. Recently he had the transmission and engine rebuilt on a 89 Toyota van (AKA Master Ace). After many issues, the van finally appears to be running well. Unfortunately the gas mileage is now terrible, 12-13 mpg instead of the 20-21 it’s supposed to get. The only remaining issue we can see is that the EGR valve light was going on for a while…but it has stopped. Was wondering if that valve could be causing the bad gas mileage, or what other potential causes might be lurking?
One thing to check is the coolant temp sensor for the computer.
If the sensor is telling the computer that coolant temp never gets up to operating temperature when it actually does, the computer will stay in the open loop mode and the vehicle will get poor fuel mileage.
I’d like add bad fuel pressure regulator, easily tested with a fuel pressure tester, bad MAF sensor, stuck injectors, and bad O2 sensor.
How many miles since engine rebuild? Two to three thousand miles will make a difference in fuel economy. It’s also the middle of winter in some parts of the country.