03 Blazer 4.3. Runs fine in park, when accelerating it hesitates and then rpms get up to 2300 and fall to 1000 and jumps back n forth. Recently had distributor changed, new plugs and wires, throttle cleaned up and it ran well for about a month. Checked the volts on the TPS and it seemed to work ok. What causes this? Any suggestions appreciated.

No check engine on, had codes read and no codes appeared.

 

have same problem,
2000 Blazer LT 4.3 vin W 125,500 4x4 automatic transmission, No codes, fuel pressure at idle 50 psi + or - 2 psi, gun the engine, fuel pressure goes up to about 60 psi and drops back to about 50 psi, shut engine off, fuel pressure jumps to 58 psi, after 13 min. pressure has dropped to 55, after 1Hr. 20 min. pressure is 41 psi, test started 1:28, at 9:10 pm the psi was 30, 11:36 pm 18 psi, next morning 10 am 3 psi, started blazer fuel pressure was slow to rise, had to cycle key three times, can't find the fuel pressure regulator. Most every time I start the engine, it starts fine, then after a few seconds acting like its going to stall, but never completely dies, it usually does this one to three times and then runs good, fuel filter was replaced about 6 to 8 months ago, I am thing the fuel pump is bad, also will I have pull the fuel tank to replace pump, my income is very limited, I am a retired truck mechanic.
Please advice what you think I need to do and witch brand pump I should by if needed.
Thank you Dennis

 

Recommend you both visit this thread and do a proper leakdown test: HOW TO: Check regulated fuel pressure, pump max output, & leakdown. If you need to replace your fuel pump, go with only AC Delco or Delphi. Otherwise good chance you'll be replacing your pump again down the road.