I havea 95 gmc Sierra sl with the 4.3 V-6 engine. Truck has run fine went on vacation let it sit for 5 days come home get in it going back to work and it's rough idling cold falling on its face will almost go dead when i stop at stop sign or just let off gas. And absolutely no power at all. I've replaced the fuel filter. Going to put new seal kit in tbi tomorrow. If that doesn't fix it I'm lost. Anybody have any ideas? No lights on 286,000 on miles, plugs wires cap rotor all a year old probably 10,000 miles on time up

 

Really surprised that no one has answered you yet. I am not a mechanic but it could be bad ignition coils, plugs or wires.
Fuel filter or fuel pump???

 

It was the fuel pump thanks for replying.