Double check the basics for now. Check the fuel filter for being plugged by taking it off and blowing through it. If you look like a chipmunk blowing through it, replace it. Afetr running it for about 10 minutes at 1500 rpms, look underneath at the catalytic converter. If it's red hot, replace it. Double check all grounds at the chassis and battery.Look at the EGR for clogged ports, wiring for frayed or loose connections and all vacuum hoses. Let me know what you find so we can move on to the next round.