ok, i have a good one here. 97 siera 4.3 auto 2wd scsb. ok truck has progressively been getting worse and worse. first time problem started we worked on it and work on it. one day after replaceing almost every sensor on it, it started running good. then 6 months later it happened again. it would start up then after awhile it would just die and not start up again till it cool. when it was running it would idle great but if you rev'd on it, it would spit and sputter up the rpm's. well come to find out the fuel pump was going bad and when it got warmed up the pump would drop to about 25psi at the rail. so we swapped in my walbro 255lph pump. truck ran good and strong. but every once in awhile at a nice cruise it would kinda hicup here and there. well today my buddies girl goes to drive it and it would start at first then it did with a bang. i think the bang was the air filter setup hitting the hood, no biggy. but when driving it spits and sputters and hicups and all kinds of nasty. won't die like before so i'm pretty sure its not the pump.

CEL is just a random cyl misfire like every other time. spark when tested last was good. maf is new egr is new and damn near every sensor on it is new. so what can it be? maybe the fuel spider harness with poppet valves? it has just been progressively getting worse. and i'm stuck i have no other ideas at all.

 

what about your coil,plugs,and wires? Are they all new?

 

he changed them all about 6 months ago when this all first started. we tried a new coil and the funny looking thing beside the coil ( looks like a heat sink with a plug on it). those did nothing. we checked spark and it was good. cam sensor and crank sensor are also new.

 

I would def check the fuel injector spider thing next......

 

is there a way to actually check it with out just replacing it?