I have a 99 S-10 w/4.3l.When idling motor will stumble & cut off.Driving motor stumble.
Vacuum lines were rotten,so replaced.Then stumbled worse.Starts right back up.No codes.
Fuel guage pegs on full when motor is started,so going to replace fuel pump.
Can anyone tell me what's wrong?Also would like a vacuum diagram to make sure hoses are right.
PLEASE HELP!

 

Check your wires on coil harness (left of throttle body when under hood) Mine did the exact same thing. Wire was broken under plastic sheathing... looked fine but when heated up, the broken wire ends would separate and engine would lose spark. Eventually engine failed to start at all. Soldered wire and still driving truck years later.

 

plugs, wires, cap n rotor is a relatively cheap $$ throw, plus it never hurts to have fresh, new clean "lighten'n'"..Altho I would assume any misfiring would def throw a code....if that doesnt resolve, then yeah, I'd be trainin my peepers on fuel delivery...fuel pumps are also cheap...it's the gettin @ it that's the PITA...I found when I replaced mine, the thing to do is the ole box "dump truck" method...good luck