I recently purchased a 1995 Ford F-250 with the 5.8l engine and the guy said it had been sitting for about 4 months and ive started running it daily again, after about a week it started smoking real bad when i shut it off and im only getting 5 miles to the gallon and only 70 miles to a tank need some ideas on what i could do to get it running better???

 

I would first find out where it was smoking from.

What did the smoke smell like? Was it burning wires/plastic? Gas/oil?

 

Change the spark plugs and while you are at it, check the engine compression to make sure the engine is okay mechanically. Are there any trouble codes? Does it have oversize tires and has it been jacked up? How many miles are on the truck? Check the cats to see if they are plugged. Is it missing? Put some Techron or Gumout with PEA in the gas tank.

 

That almost sounds like fuel injectors sticking open.