I have a GMC Jimmy with a 4.3 Vortec engine. The title says it's a 1995 but the manufacturer's sticker says it was made in Aug. 1994. So I don't know for sure which computer I have OBD I or OBD II.

In the past three weeks there have been two occasions where after driving to the store, shopping, then returning to the truck, it did not want to start. Had to press on the gas to get it going. Then about two days ago while driving, I stopped for a red light. When I went to take off there was much hesitation. The vehicle seemed to drive correctly above 1500 rpms but at idle it feels like not all cylinders are firing. Sometimes it stalls at idle. The problem persists. Still have to press on the gas just to start it. Check engine light is now on and solid.

Had a tune-up done on it 2 years ago (cap, rotor, plugs, wires). I took it to two different auto parts stores to have the code(s) read from the computer. Neither place was successful. There happened to be a mechanic at the one store I went to and he said the shop that did the tune-up did a poor job (wires rubbing on metal frame, etc.). I didn't see any wear-through on the suspect wires. I do remember though, when the tune-up was finished at the shop I backed the truck out of the bay, it stalled and would not start again. They had my truck for 2 weeks and said they had to replace the entire distributor. It was working fine before it went into the shop.

Been out of work for a year so I have no money to take it in for proper diagnostics. Any advice is welcome. Thank you.

 

Ignition modules sometimes quit with the same symptoms.
Timing light "could" shed some light on such an issue.