Alright well to start off ill just say since i bought that thing it was the worst move i ever made and ive had nothing but problems with it. Anyway I think my AIR pump may be out. Here are the symptoms. It started out in the winter when you floored it and it got up to 3000 rpms the engine would cut in and out and the drive train would as well it would jerk back just like when you floor it from take off then no power then do that over and over. Also when it was doing this you could hear a sound like arcking electricity coming from the front drivers side of the vehicle. But at about 40 degrees and warmer it wasnt effected at all. It then got worse and started doing it at warmer and warmer temps. It then began having a very slight (almost un noticible) hesitation when driving down the highway just every so often. It then started doing the complete cutting in and out at warmer and warmer temps, then it began cutting out completely when floored and now power went to the ground but the engine rpms went up to about 3 then stopped. Now it is all but dissabled and when floored no power goes to the pavement and the rpms dont go up either. It did throw the SES light on a couple times towards the beggining of the problem but it would go off after i shut the vehicle off. And it has never thrown any actual codes. I am a mechanic and my dad is as well and can work on anything from a motorcyle to loaders and semis but we cant figure out for sure what the problem is. What are your thoughts?

your description is a little confusing, however seems these blazers are VERY picky about fuel pressure, id suggest starting there. autozone rents the pressure gauge, or harbor frieght sells for 15$

And what do you mean by "air pump", like the ac compressor?

If the SES light came on, the DTC will be stored in the history file and will require a scan tool capable of accessing the history file, (the cheapie scan tools won't get at them).

GM has a TSB addressing the air pump issue.... usually causes problems at lower ambient temps, just as you're describing. The air pump is attached to the rear of the alternator and moisture getting into the system freezes and causes the problem.

As mentioned, check fuel pressure and leakdown. key on, engine off, fuel pump running: fuel pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the fuel pump shuts off.