so I have a 1998 Mazda b2500 5 speed and it gets about 10-11 mpgs. every time I fill up with gas I reset the trip meter and it only makes it to about 170 miles on full tank. I know having an older I can expect decreased mileage but this is ridiculous. I do have a scan tool and I read the o2 sensor reading and upstream and downstream matched so I replaced the converter and now the readings are normal that helped a little bit but I still get horrible gas mileage. no vacuum leaks as far as I can tell and no exhaust leaks. I replaced the plugs a while back and that was before the cat replacement so I'm gonna do that again and see if that helps. if not what else could cause this must fuel consumption? just some more info on the truck it has 269,000 miles on it, it is NOT modified in any way other than speakers and a new radio all the engine and exhaust stuff is completely stock. stuff I have replaced- iac valve, dpfe sensor and connector, catalytic converter, down stream o2 sensor, and coil packs and wires. I'm gonna redo the plugs soon.
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