94 s10 starting probs

ok here we go- 94 s10 4.3 W vin, couple days ago came up with a WONT START problem but if i let it sit overnight it will start up just fine and run for about 10 minutes and die and wont start again until i leave it sit over night again and then same thing happens(dies out, let it sit, starts yada yada yada). Getting gas-fuel pump new and "buzzing", fuel filter new, when does start fuel spraying out of injectors just fine, getting spark all the way around, when cranking-dist. rotor turning just fine-so ruling out timing chain(also since it does start after sitting all night) Timing is fine, Compresion good, wires plugs etc... all good. I even went as far as dropping cat converter incase it was plugged/re-stricted and it still has same problem. One other note- after it does turn over after sitting over nite and dies after 10 minutes it WILL NOT even start with a little help from starting fluid or gas dumped down throat. Any ideas???? Thank you,

After it dies, did you check for spark?

After it dies, did you check for spark?

Yes, it still has spark.. also noted- NO trouble codes

Let's look at this:

You said that it won't even start after it dies with the aid of starting fluid. Yet the engine has spark. You description of the problem sounds as if it is ignition. When it dies, where are you checking for spark?

Pull the cap and check the distributor shaft for play. Have seen the distributor bearings go out in more than one 4.3 of that vintage including my own '93. The star wheel will slightly rub the pickup at times and give you an erratic spark. If you check for spark you will have it but it won't be in time. It will normally start cold but as the engine warms up, the pickup will expand slightly and close the air gap. Check it out.