Changed out 4 cylinder 5 speed 1995 s10 with 1994 gmc 4.3 auto in it ran fine got 5 speed 4.3 instaled have two turn over 20 plus sec. to start bogs out befour you have two shift useing 1994 gmc computer auto 1994 4.3 gmc gas tank auto harnes on egn. if ypu jump fuel pump from pig tail on driver side it states right up i thank its the realy not sure where it is thank you Eddie

SOURCE: 1997 GMC K1500 4x4 5.7 ex.cab SFI injection system

Did you check the fuel filter?
or possably the catalitic converter is cloged, check the exhaust pressure.

SOURCE: 1997 GMC K1500 4x4 5.7 ex.cab SFI injection system

Hey there boatright33,

A few things things immediately come to mind.

There may be a problem with the engine controller. You could check the ODBII onboard diagnostics. Auto part stores will usually do this for you at no cost.

When you pulled the ones that were/went bad, how did the filters look? Could there be particulate matter still in the tank causing them to fail.

I always put this one off until last. Check the injectors. Are they gummed up?

Let me know what you find out
Mike

SOURCE: 1995 GMC Sierra

check you ideler sensor i had the same problem on

SOURCE: 1999 GMC Suburban 2500. 454 engine

sounds like fuel pump pressure. I had the same thing happen to me in a Lincoln mark VII and the electrical connection was shorting out in the fuel pump. I changed the fuel pump..Returned under warranty) put the new one on with filter and had no problem with it.

SOURCE: in-the-tank fuel pump r&r

Here are instructions for replacment with a diagram of the fuel pump components my only suggestion would be instead of draining the tank and dropping the fuel tank if you unbolt the box and using a jack and and some wood lift the fuel tank side of the box this will give you access to the tank and fuel pump/ sending unit. It will save you time and the hastle of replacing the tank straps which are prone to snapping at the threads when trying to remove the nuts.If these brake you will have to replace them.