I have a mazda 626 with a weird problem. It runs fine when first started, lots of power, etc. After about 4 mins, sometimes less, though, it runs really crappy, has no power and bogs really bad when you step on the gas too fast. It wastes enormous amounts of gas (only gets about 200 miles on a 13 gallon tank) and is driving me into the ground. Cat was replaced twice in the past year. whats wrong with it!? It has the KLZE swap from japan.