I just wanna see some options and thoughts here as it has helped in the past. I have a 98 blazer, 2 door, 4wd, 4.3L. I was on a trip when a bad rumble from the engine started and an error code for a misfire in Cylinder 5 popped up. The engine would rumble and almost seem ready to stall at stop lights and standing idle, yet seemed better at higher rpm and speeds.

The first things done were to replace the spark plugs (hadn't done for a long time), the spark plug wires (they tore apart trying to get them off), and later I replaced the rotar and distributor cap cause I was advised it looked like spark was jumping (electrical not my forte).
Once I got back from my trip I was able to take it to my mechanics who after explaing the above to, hearing and seeing the problem seemed confident that the fuel spider was the culprit along with the random misfire engine code that is now present.

Do you agree that the fuel spider is the likely culprit? Thanks for helping.

 

Simple way to tell, Pull off throttle body and look inside plenum. Should be full of carbon/black . If you see any shiny spots your spider is leaking

 

Sounds a bit like the EGR valve is stuck open, mine had the same symptoms replaced with new valve and it ran perfect again, it is sometimes possible to clean/de-coke the valve so pull it first and check before you purchase a new one.

 

Cool thanks guys