I recently purchased a 1988 Ford F350 460 manual trans truck. It was in pretty bad shape but it ran. After working out all the major issues I found that the fuel mileage was alot woarse then expected. 7MPG bad on the open road. I can live with 10-12MPG, but 7! I have no clue to why it is so bad. If anyone has any advice I would really appreciate it. One thing that is a bit wierd too, is the truck pasted smog even with this issue.

Thanks

 

Have you done a tune up recently?

 

Agreed ^^

Plugs, wires, cap & rotor, fuel and air filters all would help. Check the air pressure in your tires. Check your fuel pressure.

Also, is it 4x4? How big are the tires? What rear end gear does it have? Big tires and stock gearing will kill your MPG.

 

Aggreed X2^^

Also check the catalytic converter. My truck was doing about 8 mpg on the highway when it plugged up and my bosses '88 truck was getting about 4 mpg when its cat plugged up.

 

Yeah I went through the truck completly. It has new spark plugs, Cap, rotor, spark plug wires, air filter, fuel filter. The truck has 33's on it air pressure is at the recommend pressure on the tires. How could a guy check to see if the cat is plugged?

 

I am not sure what the gear ratio is. In 5th gear around 55-60 it is running around 2000 RPM. I would guess 3.55 to 3.75

 

I wish I could get 7 MPG, I only get about 5 MPG.

It sounds like you are staying in open loop. You might want to check the O2 sensor to get out of open loop and gets some driving in closed loop.

You could try driving it with a scanner on it to see if it ever changes to closed loop.

 

I got 14 hwy with a 3.55 geared ccswb 460. No cat, K&N filter, and E3 plugs. Got 7 b4.

 

i just got 1988 f350 with a 460 gas engine, will not start, someone said the injectors were not pulsating, any ideas please

 

I don't get it. that pretty much what that vintage truck got in the day. Maybe your askin for too much out of it.

 

Not even close to enough information to give an opinion. Can you give diagnostics. Is there spark?

 

Put a NOID light on one of the injector plugs and find out.

 

What are e3 plugs who makes them

 

E3 plugs are Chinese snake oil like Split Fire etc. A KN is a waste of time as well. A good tune up with quality parts and fresh fluids is what would be best. The 460 should get around 10-14 mpg in stock form.

 

I get about 8-10 mpg, 460, 4x4, 4.10 limited slip, K&N air filter(seemed like it made a difference all around after switching from the stock filter).