My 1994 f150 4x4 with the 302 v8 is getting about 7.5mpg and that's really bad. I'm not expecting great gas mileage but 15 would be nice. So I did my spark plugs, wires and **** and I had really screwed up the gap and it was running rough and rich with no power. So I fixed it and its running with more power and not as rich but its definitely running richer then it should. I have triple checked the spark plugs and wires. So I am trying to replace the oxygen sensor which is being stubborn. Hopefully that's it but if it isn't what else could it be? Then when I lug the motor at all or hit a bump or when I start going there is a distinct clunk or thudding noise coming from the rear of the vehicle. I was thinking U joint or wheel bearing? Also I think I blew a freeze plug because under the #1 spark plug there is a small L shaped chunk of metal on the block with a small hole in it that has coolant leaking out but my repair book doesn't say anything about freeze or core plugs. Any help is greatly appreciated.

 

Air filter maybe

 

Replaced already

 

Fuel filter done yet? Check the FPR too. If it weeps gas out the vacuum port it is bad.

 

Does your truck have dual fuel tanks? You could be losing fuel from one tank to the other.

 

How many miles? When ny 460 started getting a lot of blowby from being worn it started dumping more fuel in (was throwing lean codes). Ended up plugging the egr valve which tricked the computer into thinking all was well and dropped the fuel back to normal. Went from 8mpg to 12

 

What about the temperature sensor? I'm not sure about the 5.0, but on the 4.9 there are two sensors, one for the gauge and one for the computer. The one for the computer is right by the thermostat and if it goes bad it will ruin your gas mileage, and the gauge on the dash will still show normal temp.

 

its got 170000

 

I'll check it