[LuckyLightning]

A small update:

This past week I put in a "new" (used) gas tank, a new fuel sending unit, new spark plugs, and new spark plug wires. I figured maybe my issue was coming from one of those, even though the idle issue was much worse before I replaced those parts.

I found a very small leak right where the fuel line attaches to the fuel sending unit on my tank. I wrapped the threads in teflon tape and put it back in - this seemed to solve the gas smell I had in the cab (I also thought there might be a vacuum issue). I checked the throttle screw and the vacuum screw on the carb, adjusted them a bit in both directions but it just made the idle worse, so I returned them to where they were (although whatever idle screw adjustment I made, it seemed to keep the engine from dying although the idle was still rough).

I checked the distributer cap, because when I changed the wires the other day, there was a very small amount of play in the cap. Maybe 1/8" it was very loose but would hit a hard stop in either direction. While the engine was running, I checked and the cap was firm (no play), but I tried to very very slightly turn it in both directions: first direction (clockwise) the idle got worse, then counter-clock it got better. I kept it at about 1/8" counter-clockwise advancement since it seemed to hold the idle a little smoother.

I let it run for about 5 minutes in my driveway and it didn't die (I also took the gas cap off once or twice but no difference in idle), so I thought "okay, problem solved - just some very minor adjustments was needed and all is well."

Nope.

I took the truck for a drive around the block (I end up revving the engine very high for shifting out of 1st and 2nd because I the clutch isn't very smooth) and after getting into 4th gear and going about 40 mph, I notice a little roughness in the engine so I give a little more gas to keep the RPMs up but not really go faster. I then approach a stop sign so I let off the gas and put it into neutral as I coast to the stop sign - and sure enough it dies on me again just like it was doing the other day. Starting again takes a lot of pumping of the gas pedal and shifting requires very high RPMs to keep the engine from dying.

I'll look into changing the rubber fuel lines, and maybe blowing some compressed air into the hard fuel lines just in case something is lodged in there. I may also look at changing the ignition coil and rebuilding the carb but I really don't want to just throw parts at the problem and hope one of them fixes it. I also don't know enough about carbs to figure out if the fuel-to-air/vacuum ratio is good or not (but a rebuild may fix a stuck float problem, if that's what it is).

Anyone else have any ideas for what it could be?