a22barrette

I have a 2005 Chevy Silverado 2500 HD with a 6.0L. I was driving home the other night when the truck died on me in the road. I pulled over and tried starting the truck and it ran for a couple seconds then died. After that I could not get the truck to even fire. The only new code that showed up was P1258. I replaced the throttle body and TPS on the truck, still no luck. The next thing I did was replace the coolant temperature sensor. The truck started up and ran like crap with the Reduced Engine Power Light on. After disconnecting the battery and unplugging the TPS a couple of times the truck ran good and I drove it around for about an hour with no problems. I probably started the truck a total of 30 times yesterday with no problems. Today I was getting ready to leave and went to start the truck. Same thing as before, truck cranks over but won't start. I pulled out my scanner and now I have code P0336 for a crankshaft position sensor that was not there before. I am going to change the sensor tomorrow morning but I am really lost as to what my problem may be. I checked and I have plenty of fuel in my fuel rail, seems it may not be getting spark (all of time as it was running great yesterday). I will test for spark tomorrow but in the meantime any advice or ideas is much appreciated.