no matter how hot or cold it is outside my truck always starts very hard and rough with little to no power. in temperatures around 60 or below i plug in the block heater which helps out quite a bit. but today after school it was 99 degrees outside and STILL the truck started the same way, hard and very rough. any ideas? :dunno: 170,000 miles, superchip, and this problem was happening even before the programmer was installed. any help would be much appreciated.