My 97 Blazer throttles great when it’s still cold.
After it gets up to running temp. I try to throttle up and it bogs bucks and sometimes backfiring.
No way I can drive it like this.
I won’t even take it for a test drive last time I did it finished off my torque converter last time out.
Here’s a list of some of the work I have already done in the past 7yrs.

In order from the time I bought vehicle:

Spark Plugs
Ignition switch module
Water Pump
One Ball Joint
Idler arm
Alternator/Battery
Fuel pump (about 3-4yrs old now only about 15,000miles on pump)
Fuel filter
Cat
Muffler
O2 sensor (just one before cat)
Used Rear end (and 2 new tires for back there)
Tie rods (side’s inner, outers and sleeves)
Ball joints (all this time except the one I did before)
Front end alignment
Plug wires, Dist.Cap & Rotor.
Power Steering pump/reservoir/pulley
2 more battery (broken passenger make up mirrior was allways on slow drain killed 2 battery)
Torque Converter
Tranny Rebuild
Neutral Safety switch
Transfer Case all new seals
4x4 Drive shaft New
Rear Drive shaft new joints and balanced.
Front Diff. Output shaft both seals
Front axels
Front Hubs and wheel seals
Oil pan gasket
Motor mounts
Pitman Arm (overall most improved steering)
Replaced that single ball Joint again (my fault didn’t grease it when I did tie rods and a bad toe squeezed all the grease out.)

Yesterday I went to the bone yard and dismantled a 97 blazer with 78,000 miles on her.

Here's what I picked up and swapped out on my engine so far:
Used Spider Injectors
Used Coil/Ignition Module
Used Egr valve
Used Ac Compressor
New plenum gasket set from advance auto.
Can of carb cleaner along with a gasoline bath for the top of intake.
Truck was getting harder and harder to start.
I think its starting much better now.
When I first start it up it runs like a top.
Gets hot then it throttles up like crap.
I also grabbed a used TPS I’m gonna go change it now and see if it helps.
I’m leaning towards my fuel pump again but I never seen one go bad only after 10mins of running perfect.

 

You have to test the pressure to see if it is a problem with the pump.

Have you cleaned you MAF sensor? Are there any codes present? Sounds like the problem doesn't occur until your PCM reaches closed loop operation.

 

Was thinking of picking up a pressure gauge but everything closed now on sunday.

Got an appontment for a diagnostic scan at the shop tommorrow prob. let them gauge it.

Shop is pretty close hope I can make it there bfore she starts acting up.

no codes at all

MAF haven't cleaned yet I'll take a look.