I have a 1985 reg cab inline 6 4 spd manual. The truck has been sitting for a couple years. The truck will idle and run all day at 25 mph in town, when intake it out of town and hit 45 mph, the truck stops running. I have replaced the fuel filter thinking that was the problem. That didn't fix the issue. Could it be a bad fuel pump that can't keep up with the fuel demand? Or is there a second fuel filter? Is there another issue I should be looking at?

 

Some carbs have a filter at the inlet where the gas line connects.

 

Fuel pumps are dirt cheap. Ethanol fuel is hard on the diaphragms.

http://www.rockauto.com/en/catalog/f...fuel+pump,6256

Roadie, I believe that's exactly where the fuel filter is. It screws into the carb and the fuel line screws into the other end.

If it's been sitting for any length of time, I'd bet the carb is all gummed up, may need cleaning and rebuilding.

http://www.rockauto.com/en/catalog/f...epair+kit,5964

Another possibility is the sock filter in the tank is all crapped up.

 

Thanks for the info. I will try the fuel pump.and try to clean up the carb. if it isn't any if those, I will keep ruling things out. The truck is about 90 miles away, so I may need to tow it up here or drive it 25-30 mph the entire way.