ok yall, on my way home from San Antonio my truck was running fantastic, Got to the mid point between there and my house, turned the truck off, it sat for 25-30 minutes. Go to start it up and it is super hard to start. Get it started and it idles real irradically (but only about 600 RPM) but ROUGH! Go to put it into drive and barely runs. Can only get it to about 65 mph and it is hell to get it there (About 4 Minutes on flat ground). If I hit just the slightest incline the speed drops like crazy. So.....NO POWER, but No smoke either. Feels like either air in the lines ot a bad fuel filter. Replaced the Fuel Filter, same problem. WHAT CAN IT BE? Please help ME!