Ok my 97 chevy 2500 4x4 with a 5.7L has something wrong with it and i cant figure it out. Heres what is does....If i punch the gas to the floor the motor revs to about 2.5 to 3 thousand Rmps (when it use to go all the way up to the rev limiter) but it just bogs down and stays a 3,000 rpms until i let the gas up a little then it picks up and goes had my buddys brand new snap on scanner hooked up did some tests on it and its all good.(except at one point the o2 sensor flashed a code to the computer but it only has something to do with the heater wire) The only thing aftermarket i did to it was put a catback exhaust system on it at my work all that has is 2 xcelerator performance mufflers on it with 3 inch tailpipes straight out the back. its true duals cause it has 2 cats side by side so it just put two mufflers on it. Any info would help cause its a 2500 and it feels like its got a 4 banger in it.