HELP!!! 1984 f150 straight 6 won't start!!

I started up my 1984 f150 to let it warm up and left it running for about 45 minutes (way too long, but anyway) and I went inside the house to get something for my friend and when I came back out the truck had started missing real bad to the point to where it was about to die. It ran very rough and we could not figure out what the problem was. We just installed this motor about 6 months ago. It only had 45000 miles on it and we replaced everything we knew how to replace, (i.e. oil pump, flywheel, timing gears, ignition module [which went out after this situation happened and I replaced it], coil, distributor cap, rotor, spark plugs and wires, carburetor and the complete exhaust system). All timing was correct, it ran and sounded sweet then. I also took my distributor out and it checked out yesterday, its good. I thought a nut from the screw which holds the breather cover down had fell down from the carburetor and into the motor so I took the head off but didn't see it, but in the process of taking the head off, I forgot to drain the water out of the motor before lifting the head from the block. Right now I have to change my oil to get that antifreeze out. I replaced the carburetor again and it ran better but not right, still missing. It started it up after I put the head back on but still didn't run any better. I believe the ignition switch is bad because it started going out to where when I turned the key, it wouldn't say anything unless I slammed the door or something and now I have to push the ignition rod down to try to start it. I don't think the ignition switch would cause it to miss and the other stuff but I don't know. Also now, it won't come out of park even into reverse. It will barely shift out of park but not completely into reverse or any other gear, which just started happening after I put the head back on and STARTED IT UP and backed up about 8 feet from the door of my garage back to my parking spot in my drive way which is on an incline, not steep. I'm not a real mechanic I just got some books and had a good friend to help but we are both at a stomp after I change the oil and the ignition switch. I KNOW THIS IS LENGTHY BUT I'M DESPERATE FOR ANY HELP I CAN GET. :banghead: Thank you in advance

Maybe picked up some water?

Go ahead and perform a compression test. I believe a 15 % variance is
acceptable. If it's that much or more between the lowest pressure and the highest, there's a problem. If it is more, put a teaspoon of oil into the plug hole (one at a time) and spin the motor over to recheck the pressure. if comes way up, you've got a ring problem if no increase is there, your valve is likely to be burned. DID you use any starting fluid, sometimes you can use to much and wash the oil off of the cylinder walls causing low or no compression. I did't catch wether it was EFI or not. Remember essentials, Timing,Fuel and Spark. any one can screw you up. Hope this helps.

ervinj

Go ahead and perform a compression test. I believe a 15 % variance is
acceptable. If it's that much or more between the lowest pressure and the highest, there's a problem. If it is more, put a teaspoon of oil into the plug hole (one at a time) and spin the motor over to recheck the pressure. if comes way up, you've got a ring problem if no increase is there, your valve is likely to be burned. DID you use any starting fluid, sometimes you can use to much and wash the oil off of the cylinder walls causing low or no compression. I did't catch wether it was EFI or not. Remember essentials, Timing,Fuel and Spark. any one can screw you up. Hope this helps.

ervinj

When I took the head off, I noticed #5 valve was black (I assumed it was carbon) and scraped it off with a flat head screwdriver-did I make a mistake by scraping it off? No, I didn't use any starting fluid. All spark plugs are black again so I going to replace them again to see what happens. If this doesn't work then I'll try to do a compression test. Even though I don't know how, I'll either find out or have someone do it. Thanks

When I took the head off, I noticed #5 valve was black (I assumed it was carbon) and scraped it off with a flat head screwdriver-did I make a mistake by scraping it off? No, I didn't use any starting fluid. All spark plugs are black again so I going to replace them again to see what happens. If this doesn't work then I'll try to do a compression test. Even though I don't know how, I'll either find out or have someone do it. Thanks

I also have an inline 6 that had to sit for a while. When I started It back up it ran rough and somtimes would stall and jump etc. anyway all it turned out to be was one or two of the plugs was fouled and changed them. After that she purrs like a kitty.

Don't forget to check the obvious connections on the battery terminal heavy gauge wires and the grounds and make sure they are not loose.

We have a vehicle that has lights but would not start and if you slam the hood then it will start. It turns to be just a heavy gauge wire not tightened enough and barely makes contact when the vehicle is shaken (ie when the hood was slammed closed).

Some problems with rough running is that the spark plug wires (even new) was rubbing on the engine block and worse rubbing on the exhaust manifold and some cheap spark plug wires are cross-firing since they don't have a good insulation. Use a spark plug wire separator and use some tie-wraps to keep those spark plug wires away the engine block or heat sources or from each other.

The problem is your key switch. the key switch isnt sending enough power. once u change it your truck will run perfect.