1998 Chevy S-10 I am completely baffled.

I was driving down the interstate one day and noticed my temp. Climb to about 210 (it normally sits at 200) and thought it was odd. A few minutes later, when I would put my motor under a load to accelerate slightly I would get a slight ticking noise. So Is topped at a store and came out to start my truck to find where the noise was and it wouldnt crank. I tested for spark, it was good on 2 cylinders (so I assumed they were all good). Tehn I checked air flow, it was good. Then I checked for fuel, the only way I had to do this was by using starting fluid. I sprayed some starting fluid in the motor and after a little hesitation it cranked right up. So I had it cranking and a buddy of mine told me to pour some "sea foam" down my vaccum line off the booster. I did and it reved real high and shut off. I cranked it back up and it was running a little rough. Which led me to believe maybe I met of gotten some bad gas at the bottom of the tank, so I went to a gas station 200 yards away or so, turned my truck off and filled it with premium gas. And poured the rest of the "sea foam" in the tank. I drove about 4 miles in town and the ticking came back and was getting louder and louder, but only under a load. I parked at my friends house and about 15 minutes later went outside and it didnt want to cranout 10 seconds, then fired up and the noise stopped but it was running rough still. I drove down to then end of his street and the noise came back just as load as before. I drove bout 2 miles and the noise was hapening all the time and shut it off. When I went back and tried to crank it again I got a puff of black smoke and the noise was even louder so I shut it off imediately and towed it home. After troubleshooting with an ex mechanic for a while we decided to check the push rods, maybe one had gotten bent. So I pull all my push rods and none of them are bent. So back to the mechanic, and his only explanation was a spun bearing, but I was determined to decide otherwise. SO next I decided to check my fuel system maybe I had bad gas and it clogged up something. So I replace my fuel filter and still need starting fluid to get it to start, but when it starts it was running a little rough but not a whole lot to worry. So I let it run for about 30 minutes and off and on rev the motor to about 4 grand, and I hear no noises. I turn the truck off thinking I might of cleaned out watever it was and it wont start again without starting fluid. So then I decided to check my fuel pressure on the rails. I checked the pressure and it was 44psi then dropped down to about 38psi, with key in on position. The haynes manual stated the correct preuure was 41-47psi and then a 3-10psi drop, so I believe it to be correct. Then I decide to check my injectors, maybe one might be clogged. Pull my intake manifold back and crank it over and all the injectors are putting out a good mist. So I decide its not that. Next maybe the spark? I pulled all the plugs, which were just changed 5000 miles ago. And there all fouled up with gas and crap. So I go buy a brand new set of plugs set the gap to specs, .050. Put them in and same story it wont crank without starting fluid and runs pretty rough. I went to the parts house ordered a ignition coil and it should be here in the morning.

Wat is my problem? Ive been messing with it for 3 weeks and I am completely baffled with what the problem is. Can anyone take a stab at it and give me your input it would be greatly appreciated.

Ohh and also, when I get it running the check engine or service engine lights do not come on. And the motor does not make any noises, but I also havnt putten it under a load either. Its been sitting on stands in my driveway.