93 4.3 V6 performance problem ...

[quick66ss]

I have a 93 GMC with a 4.3 and a 5 speed. The truck has 190,000 miles on it but has been well cared for. The truck has a problem that I have not been able to figure out. It is the reason the previos owner sold it. I have done a tune up as well as a fuel pump/filter. The problem is at part throttle it seems to stop or surge and not accelerate. If you floor it it goes just fine. I have resorted to just giving it full throttle when driving it when it tries to bog out. The plugs look great and the compression check shows all cylinders around 175. I have no check engine light either. The truck runs great other than the part throttle bog. Does anyone have any ideas?????

[drumset5994]

I was gunna say CAT, but i figured they either didnt have them that year (i dunno) or i saw you had no light on.

 

*scraps that idea*

[quick66ss]

New cat and flowmaster exhaust as well as a new EGR valve. I also replaced the TPS switch.

[shorgasm]

New cat and flowmaster exhaust as well as a new EGR valve. I also replaced the TPS switch.

 

<{POST_SNAPBACK}>

 

 

LOL....My little 93 4.3 auto does this.....oddly enough the O2 sensor was the culprit.

 

It would feel like it just layed down and would NOT accelerate....put the pedal to the floor and Wham!!...It would take off.Mine would do it right before the 1st to 2nd shift.Even more so when it was hot out or I had been idling in traffic for a bit.

 

It completely cured mine....odd thing was the Engine Light came on once and wetn off yet it was still bad.The light never really coincided with the problem.Sure annoyed me though.I though for sure it was the Injector leaking...