doing research for a friend,, he has a 93 s10 with 4.3l vortec and had the fuel pump replaced and after that the truck has no power it just spits and sputters when you rev it,, they again replaced the fuel pump, still same thing, then fuel filter, catylitic converter, complete tune up, swaped injectors with another 4.3 still no power,, when you watch the fuel injectors when reving it up they spray fine then when the motor starts spitting the injectors go to a dribble, and if you spray carb cleaner down the throttle body it will then rev up until you stop spraying,,, LOOKING FOR HELP,, BIG HELP,,, maybe pcm??

 

fuel pressure regulator?

 

i am going to look into this but in the mean time i will take some more suggestions

 

Did they replace the fuel filter?

Sounds like you have crap in teh fuel lines, engine runs fine at idle, but once you run up the rpms she is starving for fuel. Fuel pressure regulator is a possibility as well.

Have they tested thefuel pressure?

Which injection system does he have. TBI or CPI? Vin W or Z?
TBI is like 20psi, while CPI is like 60psi. Huge difference. Got the right fuel pump?

 

so into the investisation so far we found this is the early vortec which seems not to have a regulator due to the throttle body and if it does its above the tank which we have not had enough time to drop the tank again,, fuel lines have been blown out with air with everything dissconected,, so if anyone knows where the regulator would be on a vortec throttle body let me know,,, this one has several mechanics stumped

 

You have the TBI fuel injection system then.

Have you tested the TPS and IAC yet?
It could also be a MAF, but I would do the TPS first.

It possible the TPS isnt sending the signal to the puter to feed more fuel.

Has anyone pulled the codes yet?

 

no,, there hasnt been any codes pulled,, trying to figure this out in a very very small garage,, we have swapped the MAP and nothing changed,, but have not tryed the TPS,, that will be tomarrows thing,, am really still up to more suggestions