Surging

I own a 1986 GMC S-15 Gypsy 4x4 5 speed TBI 2.8 V6 with and RV Cam

When I am driving in first or second or even third the truck seems to move forward and back a lot. It recently had a new MAP and Oil Change, New Plugs Wires Cap Rotor, and filters. Could this be due to the EGR Valve. I have had this SES light come on and saying its a bad EGR Valve but when i depress the valve the engine stumbles like its about to die.

Also for no aparent reason, after driving on the freeway or highway the truck will stall. but starting it right back up and its fine.

when was the last fuel filter change? PCV?



I own a 1986 GMC S-15 Gypsy 4x4 5 speed TBI 2.8 V6 with and RV Cam

When I am driving in first or second or even third the truck seems to move forward and back a lot. It recently had a new MAP and Oil Change, New Plugs Wires Cap Rotor, and filters. Could this be due to the EGR Valve. I have had this SES light come on and saying its a bad EGR Valve but when i depress the valve the engine stumbles like its about to die.

Also for no aparent reason, after driving on the freeway or highway the truck will stall. but starting it right back up and its fine.

about 3 months ago for both