I have an 04 Blazer 4x4 4.3 Vortex...here's my problem. Cats were going bad, so in an effort to save some time and money, we cut the cats off and just welded straight pipe on. That's when the issue of over heating started. Thought it was due to a possible bad thermostat. Took it out, she still over heats, thought it might have to do with an exhaust leak, fixed that, problem persists. Noticed that the clutch g fan want working right. So to it of and replaced it with an electric on with a toggle switch inside. Even with the fan, she is still running hot.
Previous to replacing the fan, when she would get above the halfway point on the temp gauge, she would start to super and act like she wasn't getting enough gas. We let her sit for a bit to cook off and she would be fine. That is till last night... She has been doing pretty good but last night when we came back out to her to go home, sincerely she won't start. If we put gas in her to end she would fire up but only till that gas was gone. I think our timing chain/belt is the problem, he thinks it's the ignition coil.... What do y'all think?

 

I assume that the first thing you need to do is get the truck to start. If it only starts with gas down the intake then it’s not getting gas or the gas in the tank is bad. Do the fuel pressure leak down test in the sticky first.

After you can get it to start and run then we can look at the over heating issue. Are you sure that the cooling system is bled properly? Do you have a recent compression test?

George