What would cause a 1988 Chevy silverado to stall cut out hesitate or surge when idlng already replaced fuel filer throttle position sensor o2 MAP and you blocked off the egr?

There are a few things that could cause a 1988 Chevy Silverado to stall, cut out, hesitate, or surge when idling, even after replacing the fuel filter, throttle position sensor, O2 sensor, MAP sensor, and blocking off the EGR. Here are a few possibilities:

* Vacuum leak: A vacuum leak can cause the engine to run lean, which can lead to stalling, cutting out, hesitation, or surging. Check all vacuum lines for cracks or leaks, and make sure they are properly connected.

* Faulty ignition system: A faulty ignition system, such as a bad spark plug, spark plug wire, or distributor cap, can cause the engine to run rough and stall. Check the ignition system components and replace any that are damaged or worn.

* Fuel pressure problems: Low fuel pressure can cause the engine to stall, cut out, or hesitate. Check the fuel pressure and make sure it is within the manufacturer's specifications.

* Clogged fuel injector: A clogged fuel injector can cause the engine to run lean, which can lead to stalling, cutting out, hesitation, or surging. Try cleaning the fuel injectors with a fuel injector cleaner or having them professionally cleaned.

* Computer problems: A problem with the engine computer can cause the engine to run rough and stall. Have the computer scanned for trouble codes and diagnose any problems that are found.

If you have checked all of these things and the engine is still stalling, cutting out, hesitating, or surging, it is best to take it to a qualified mechanic for diagnosis and repair.