Still won't idle..

I literally have everything sealed off. I feel like I'm missing something. Does anyone thing that it'd be a blown head gasket? The truck has been sitting for months and I know that I had new oil in it. Now theres water in there, not a lot, but I don't know if it's just from sitting out. Also, if I need to check my head gasket, can someone walk me through the process? I've got about $800 left to put in this truck and I've got to much in to sell or scrap.

Pull all of the spark plugs and do a compression test on each cylinder. You'll need a compression tester......basically a hose with fittings that allow the hose to screw into the spark plug hole and a gauge attached to the other end of the hose.

With all plugs removed, and the gauge attached to cylinder #1 (closest to front of engine), crank the engine over at least 10 full revolutions with the starter. Read the number on the gauge and record it........do the same to the other 3 cylinders and post your results here.

All of the readings should be fairly close to the same......maybe 10 lbs difference or so, and all being above 130-140 lbs if the engine is in good shape.

Is the carb/throttle body or intake leaking, lose hence vacuum leak? Have a stethoscope to listen for leaks?
Do the compression test with the throttle blocked open.
When you do the compression test, write down the reading on each cylinder test as it is tested.
If compression is low on any cylinders, squirt oil in cylinder One, check the compression again, same number of turns, write it down; then cylinder Two, yada. If the readings are noticeably better, rings are bad. If not, probably the valves leaking on low cylinders.

If compression is good, may well be the carb if not a vacuum leak.

Free loaner compression test tool from Autozone