95 s10 blazer 4.3 vortec vin w rough idle

There is only one map and knock sensor... sounds like an internal fuel leak. Either the regulator is leaking or the lines inside the plenum going to the fuel injector spider is leaking, those lines are referred to as a nut kit. This can be tested for by checking fuel pressure and leak down rate. It shouldn't leak down much if any over 5 min. If you don't have a tester cycle the key a few times to allow the pump to run, turn it off and wait 2 min. The go behind the intake and press the Schrader valve on the fuel line, if no fuel comes out then your fuel pressure is leaking down. Take the upper intake off and look for clean spots, that's where the leak is. Everything should look dirty and black