We had a customer who just brought this beautiful black Chevy for us to do a dyno pull so he could see what kind of power it was making. After the results came in lower than expected; we found a clogged fuel filter and a dirty air filter. The customer told us to replace those and while we were at it to go ahead and install a tune file for towing. Truck gained 100 ft./lbs. of torque and 69 horsepower. Needless to say; they left very happy.