Poor gas mileage

CONRADD72

MEMBER
1999 MAZDA B3000
3.0L
V6
2WD
AUTOMATIC
180,000 MILES

My truck is having serious gas mileage problems and it has been happening ever since I got the truck. It has no check engine light and the obd is responding. I changed the plugs, oil, air filter, and had the injectors cleaned. The gas mileage problem only occurs if I go 50 mph or under, therefore I get much better gas mileage going over 60. The throttle body is responding properly and is not sticking and the truck does not surge or over rev. I was thinking about replacing the EGR valve, EGR vacuum solenoid, canister vent valve, and vapor canister, but would like to know if that is even going to help or that there might be a different problem going on.

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Usually a tune up would help here. Since you changed the spark plugs already I would recommend replacing the spark plug wires, fuel filter, and the air filter. New spark plugs will only spark with the current the comes over the spark plug wires, so the two should be replaced together. Also I would recommend checking the gap on the spark plugs. In the diagrams down below I have included the Original Equipment Manufacturer[OEM] part number for the spark plugs for your vehicle, including the gap. Please pay attention to the last note on this diagram. I have also included the instructions for the removal and installation of the air and fuel filter for your vehicle as well from the vehicle manufacturer. Please go through these guides and get back to us with how everything turns out.

Thanks,
Alex
2CarPros

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