i have a 1994 s10 blazer 2wd. v6. fuel pump, filter, plugs,wires, cap, rotor, control module, tps, map all replaced. starts great. idles great. even when cold. at half to 3/4 throttle, it hits a flat spot. you cannot smooth it out or regain rpm until you back off the throttle. co. smells high. it has not been driven yet as i am getting it ready for the road. it has good power. you can power brake the thing and it will raise the back end up. i dont know what else to do. it does this when you first start it up and never changes the spot where the hesitation starts. it dont have to be running for it to do that.

any ideas ... would be great ty.

 

Is the ECU getting the proper signals from the MAP and/or TPS sensor?

How's the fuel pressure & leak down?

Have you checked back pressure at the upstream O2 sensor location? If the catalytic converter were partially plugged, it could cause what you are experiencing.

 

i havnt checked that out yet. the fuel pressure is good. i thought about the cat. or ... the o2 sensor. there is no check engine light on. im also wondering if the cpi could be failing at that rpm. i did drive it once .. it runs like a bat outta hell. until you really step on it then it keeps going but has that stumble. kinda maybe like shortage of gas. f.p is new as the filter.

 

I take it you didn't monitor the fuel pressure while the condition was being experienced.?

 

checked the cat. its in pieces inside ty for all the help