I have a 2000 Pontiac GP GT K engine and it misfires intermittently at idle and while driving and most notably in fourth gear when the lock-up converter is engaged. I tuned up the engine with new wires, plugs(autolight), coils. Ran numerous bottles of injector cleaner through the tank, ran dry gas thinking there might be water in the tank and changed the gas filter. The cat has been removed about a year ago, it broke and was ratteling. I Replaced the EGR valve about a year ago for a similar problem. The engine has 200,000 miles on it and runs very well, no oil burning at all and is very strong. It has a fresh air intake on it and that is about it for mods. The engine will miss at idle in park and the tach gage will fluctuate from 700rpm to 1200rpm. The misfire is very pronounced in forth gear while lock-up is on. Im thinking maybe a partial clogged injector or may the EGR is malfunctioning, or maybe the body computer, it seem like its affecting all injectors, almost like its cutting out for a split second and this occurs while the engine is hot. I just dont know where to go next? I dont want it to turn into a money pit by replacing everthing with a hit or miss deal. I only had one code for the cat flow, forgot the code number but was because I removed the cat. Any help will be greatly appreciated...Thanks...Tom
