i just finnished doing the math and i found out that i can afford to run a hummer. there is something really wrong with my old rig i'm only getting 5.7 MPGif you feel i did the math wrong i had 82 leters in my front tank and it only lasted 200KM

i have no idea what is wrong i'v changed the distro cap and rotor, plugs, and wires still no effect. any ideas on what could be wrong?

i'v done a compression test and it looks good but i think it got 2 compression srokes on one or more cyl.

it's an 88 F-250 302 injected 5 speed man. stock tires. it seems like it's lifted but i'ts not. ohhh ya 4x4 but no front drive shaft (can't find one well i can but it's over $500)

 

As always.. start at the computer. Check for codes and also check that all the sensors are present and plugged in, O2 in the exhaust, air and coolant temp sensor in the intake, MAP sensor on the firewall.

 

Bring it in for a tuneup get a fuel system flush, get a fuel tank additive, both clean the fuel lines, also check if you have a leak? kinda hard to believe you get 5mpg either way though...

 

I did rough figuire of liters to gallons and you should do better than that. I had an 88 F350 5sp 4x4 w/120000 miles from Original owner .Body great But when I got it the oil filter was actually rusted out(had date of change on it 4 years and 50000 miles prior ). This truck ran well and even not being service for years (which I took care of) Got 10.5 MPG (US) on way home when bought. And got up to 12 MPG on trips after services.
Check wires caps , get motorcraft parts . Even though ac are suposed to be same I lost electrods off emm.

 

Check to see in you have a crossflow problem between your two tanks. If one of them crossfills to the other and overfills it the fuel will be pushed out the vent hose, which will go into the vapor canister below the battery (if the seal is good, or dump out around the top of the tank if not) .... if this is hooked up it should smell strongly like fuel. Whether it is hooked up or not, you should be able to check it by putting a catch pan under the truck in that area and start it and let it idle for a while ... you will see the fuel dumping out if this is the case.

 

this just tells you how good the local ford dealer is here. i took it there to get a full inspection done. they said "it runs a little rught when your bogging the motor other than that it's all good"

so i have to self dignose the problem. i had my truck parked in a shop for 3 days and there wasn't a drop a fluid leaking anywhere. the tanks where both dry. we even checked the rear main and believe it or not it looks good. it's the firs 302 that i'v seen with no leak there

ohhhh ya i'v even changed the fuel pump too (thanks to the fuel pump relay) the relay died so i bought the pump and the relay, when i only needed the realy. but it is good to know you have a good pump so i kept it.

 

i know it's years later but i did find a leading cause to not finding problem. it was the guy operating the compression tester. #1 cyl was very low on compression. it got to the point i would only get 600km out of the plug on the #1 cyl and i think 20psi after 3 strokes tells me something is wrong.
the old rust bucket is gone now. i decided after parking it for a year or so due to a trans leak. while it was parked i forgot why i did so, i thought it was just fuel mileage. so i threw it back on the road and burnt the tires off it for 3 months. one day i was towing a jeep 91 Cherokee out of no where a loud bang and awesome grinding sound.

so my buddy was working on mounting a 38 intersmashable cab on it, with a 460 power-plant. it looked awesome but i have not seen it finished