I have a 92 sierra,4.3, new coil,plugs,wires,cap,rotor,and ignition module in the dist. Rebuilt the tbi, It starts fine,surges a little at idle, put it in gear and move and it cuts out,misses,and acts like its running out of fuel,fuel pressure is fine,when I hooked up a timing light my timing marks were VERY erratic, jumping all over.any ideas or sugestions? thank you

 

Check for vacum leak. Use starting fluid and spray in short bursts around the whole intake and see if the idle goes up when you do.

 

checked for vacume leaks, all ok there, checked fuel presure again and noticed it was dropping, pulled the tank and the hose between the pump and tube had split while I'm there I'm putting in a new pump and strainer also, thanks for the help so far, sure I'll be back!