Truck won't idle

[OJ1988]

Okay, as I am starting to drive this truck, I guess I am shaking out some bugs.


First a little background. I bought this truck a month ago. It is an 86, was a 4.3 but the guy I got it from swapped in a junkyard 350. He said it came from an 85 van.

It has a Quadrajet carb, and looks all stock. There are a few things not hooked up, egr, charcoal canister. And the fast idle solinoid, I do not know were it should get vacume from, it was not hooked up when I got it.

I have put about 200 miles on it and it ran well.

Then the other night, we drove around the town and got something to eat. After eating, we came out and got in the truck. It had been sitting for about 1.5 hr. I started it up, and it was idleing real rough and low RPM, If I gave it a little throttle it would smooth out.

Drove it home. As long as you were giving it a little gas, it was smooth. But without it, it would shake and stall.

The next morning I got in it and it ran fine, then that afternoon, same thing.

So, I started looking over things, cleaned the carbn with some carb spray, changed the oil and filter (needed this anyway). Put some new plugs, cap and rotor, and wires.

The plugs actually looked pretty good. I put some Lucas fuel treatment in the tank, and changed the fuel filter, it looked real bad.

After these changes it ran much better, but once it warmed up, it did the same thing.

I checked for vacum leaks but could find none.

I tried to check the timing, but there is no timing tab.

The top gasket on the q jet does look bad, and leaked slightly, but spraying around it with carb cleaner did not change anything, like a vacume leak would.

So, I am at a loss. I am going to pick up a manual to check all the vacume lines and such, and try an find where to hook up that fast idle.

The only thing I can think is the carb, think a rebuild is in order?