I have a 1998 Chevy k1500 5.0L Vortec. It began having a problem where it would jerk intermittently while i was driving and when at stoplights or very low rpm's the engine would turn off on me. It would turn off after it idled erraticly, dropping low and raising up again, but would start right back up immediately and have no problems for a little while. That can be "fixed" by giving it a little gas while keeping on the brake at a stoplight. I replaced the fuel filter in august, got a new fuel pump in December, and had a tune up done this past month. It runs better after the tune up but i still have the problem. The service engine soon light is constantly on and I have tried three different code readers on it and none of them were able to connect and get a reading. I have no clue what to do with it anymore.

 

Bring to a radio place have then look at wires
You/we need codes or its just guessing
Start small look at filter then ignition/wires/injectors there's about 100 things it can be

 

Try Autozone, they will read the codes for free. Hopefully their code reader will connect.