I have a 2000 Chevy Suburban, with error code p0300. I've researched and know that there can be several reasons...coils, catalytic converter, computer and so on. I'm the fix it yourself mom and thought I'd start with the easy, replaced the coils. The problem continues, hard to crank, loping motion when in idle, and goes dead periodically in idle. But, this weekend my negative cable had worked it self loose causing complete power loss. Tightend the cable and wa la, service light went off, car began cranking normally again and no loping while idling. Until the next day, sitting in idle and the car went dead. light back on etc... Is this a grounding issue, or a computer issue or possible both? Thanks

 

Are you still getting a check engine light? I had the p300 code and had to change my plugs out

 

Welcome to the forum,
You might want to consider replacing the ground cable at being 11yrs old and may want to consider replacing the positive cable to the starter as well.... the cable may look fine on the outside but can corrode and break down inside the jacket.

 

Thanks for responses. My friends mechanic husband. Found my problem. Fuel pressure regulator. 40 bucks and its fixed!