Chevrolet Repair: engine hesitation, loss of power., throttle position sensor, engine hesitation

Question
I have a 1988 chevrolet k-5 blazer, it recently had a tune-up; plugs, oil change, egr valve replaced, and also had it "scoped" by a local mechanic. I was told the engine is running within specs, but it still feels like it has a hesitation or lack of power as I increase speed.
  Any suggestions?  

Answer
Hello Michael,
I would check the fuel pressure, on the throttle body side of the filter. It needs to be a full 13 PSI, or will be low on power.
I have had a hose inside the gas tank where the pump connects to the line, get a hole in it, and only put out 7 PSI at the filter. The rest just sprayed inside the gas tank. Idled good, but very low on power, and bucked when accelerating.
If the fuel stays at 13, then the throttle position sensor could be bad, and still not trip a code. It can be checked with an ohm meter. You just unhook it, and while probing the terminals, work the TPS through its complete range of motion, and the ohm meter should go from one end of the scale to the other....smoothly and consistently.
Maybe not the full scale, but a good consistent reading, each time. No skips or jumps.

A plugged exhaust system could also cause the power loss, but generally more noticable at higher rpm's.

Van