I have a 02 Suburban 1500. It starting running ruff and shutting off every now and then and became worse till it wouldn't start. We changed the fuel filter and the fuel pump relay under the hood. Primed the system and it fired over but was ruff starting. Check engine light came on so after testing that we replaced the coolant sensor in the side of the block since it said it was bad. Still ruff starting every other time till the last time it shut off and doesn't want to start back up. Not sure where to go from here.

EGR valve could possibly be stuck open. It is an electronic device on these years vehicles....could remove it and clean it, see if it makes any differences. I think it is attached with two 10mm bolts. Easy enough.

What is your fuel pressure indicating?