OBD2 Codes

I need you guys help. I purchased a 2002 Silverado 1500 (5.3) FLOOD vehicle. The engine had water in it. I now have it running but it has no power. The OBD2 is reading the following codes: 0106 (Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem) AND 0300 (Random/Multiple Cylinder Misfire Detected), Any help would be greatly appreciated. HELP, HELP, HELP... :(

does it idle like crap? I first would replace the MAP Sensor ( Manifold Absolute Pressure) if you have a true Misfire then see what cylinders it's on. If the misfire is on all cylinders then chances are you have bad ign. parts

does it idle like crap? I first would replace the MAP Sensor ( Manifold Absolute Pressure) if you have a true Misfire then see what cylinders it's on. If the misfire is on all cylinders then chances are you have bad ign. parts

Thanks BIGT2317, I replaced the map sensor. The misfire problem was found to be cylinder #'s 7 & 8. WHAT'S NEXT? Also the injectors were checked and they are fine. THANKS in advance.

Check the Plugs. You need to replace all the plugs anyway, or at least i would if water was in the engine! after the new plugs are in and the misfire is still there, then check the ign. wires for voltage any auto store has a KV Tach they can be checked with. if the wires are good them it is probably the coil packs on those cylinders
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