2000 gmc engine light is on then it blinks and the vehicle surges?

Answer 1

if your check engine light is on and it is flashing it means you have an engine misfire, do not drive far with this vehicle as it will send so much unburnt fuel down the exhaust and burn up the catalytic converters which if not within the federal warranty of 8/80,000 then will be costly for factory replacement. If you are anywhere near 100K miles change the plugs, and depending on what motor you have it could be either a coil gone bad, cap and rotor on the some motors, wires, etc. It is possible that your mass air flow sensor could be bad however unlikely problem on these trucks. the other problem may be lack of fuel, try changing the fuel filter and checking the fuel pressure at the rail, if it drops too quickly you may have a bad fuel pressure regulator which would dump fuel down into the cylinders and create the misfire as well