Well, there seem to be many other similar threads (one of which I've posted in a bit: https://blazerforum.com/forum/engine...r-start-61358/), but I haven't been able to come up with a solution, & I don't want to usurp someone else's thread, so Here it goes.

I have a 2001 Jimmy, 2dr, 4.3 Auto.
Issue I am having is (maybe two separate issues):
1 - Hesitation / no throttle response sometimes after cold start.
2 - "Heavy" loading on the engine intermittently when moving from a stop, generally 1st & a bit into 2nd gear, sounds like the engine is straining really hard.

-- Currently NO CODES being kicked out --

For a little background.

I purchased the truck 2 months ago with about 110,000 miles on it & a couple weeks in started getting a P0300. Went through all the motions, Replaced plugs, distributor, fuel filter, TPS, upgraded CPI to EFI, & finally the fuel pump (<-- which actually fixed the P0300).
Wish I'd thought of that one first..

It should also be noted that the only one of these replacements I did myself is the TPS.

Distributor, plugs, filter & EFI were done by a local shop, & plugs (again), filter (again) & fuel pump were done by the dealer.

Based on the thread I mentioned above, I unplugged the MAF & cruised around for a bit, it generally seemed more peppy, but eventually it started straining again (I hope this description makes sense).

Really hoping someone will have some insight on this

 

okay, I haven't had much time to tinker the past few days, the one thing I did do was clean the maf.

This seems to have helped with the hesitation, but has done nothing for the engine straining. it is still happening intermittently.

Next up, maybe clean / replace the egr? anyone have any other thoughts?

 

I would check the EGR valve as well as the TPS & MAP sensor inputs/outputs.