I just bought this truck about 2 moths ago. The guy said it use to run good but then . just started being doggy. i bought it for $300. it had a hard time going 70 on the interstate and 5th gear was just for show. I cleaned the carb, the choke was sticking so I thought that was the problem. It was not. My wife has been driving it to work. Last week she got into town called me saying that the engine died on the interstate and that she blew a coolant hose. I picked it up put a new hose on it. It took for ever to get it started but it did start and once its started it seemed to run at idle just fine. If i turn if off let it sit it starts real hard again. I tried to drive it now it will only do about 40 mph tops. I did a compression test and am only getting about 115 psi throughout. I was thinking that was my original problem and needed a new head. But now i cant get the thing to run hardly at all. Think I could have a bad spark problem?

 

It wouldn't hurt to check the ignition system. A bad cap and rotor can cause it not to start. You might at least get it to run enough to work out the other problems.

 

115 should mean the head gasket, valves, and rings are good. Tune-up sounds right. I would check the vacuum advance and timing after the tune-up. IMO

 

Check your fuel filter. I don't know that much about engines, but I have had a few 22Rs and one of mine would chatter at 70mph... it would run fine at 69mph. Come to find the fuel filter was clogged with rust and would starve the engine for fuel. Once I hit 70 it would die, jump start, die, jump start... that was the chattering.

Even if I am wrong the FF is well worth changing.