Morning! I was out at our hunting ranch this weekend.. trying to get my ranch truck running. It has ran great for the 4 year I've had it but died one day about 3 months ago and wont stay running. 1991 GMC Sonoma 4x4 with 4.3l v6. Here are the things I've tried over the past few months, replaced the fuel filter then the fuel pump. Rebuilt the TBI injection system and cleaned up to shiny new. Replaced all gaskets and fuel injectors. I've replaced the pcv valve, throttle position sensor, air idle control and the ignition control module. Spark plugs and wires were replaced about a year ago. Here's the deal.. The truck will start and idle up for 5-8 seconds and then tone down to normal idle and shutters/shakes and dies. With the air cleaner off it would even blast a quick fire ball out of the throttle body, we tried starting it about 20 times and it sent fire out about 3 of those times. I don't want to put a lot of money into it as I only have maybe $1300 into it total. It's been a great truck and a workhorse on the ranch.. Can you guys suggest a few ideas to get it going again? I'd certainly appreciate it! Thanks!
Blind shot from the hip: Pickup coil/distributor. Use a timing light to test the firing on each plug wire, checking for intermittent misses on each.