I have been having this problem, where if the engine isn't completely warmed up before driving, the car will hesitate and then backfire. Once it gets warm it runs and idles fine. So far I have replaced the air filter, repaired some leaks in the air intake hose, cleaned the IAC, flame trap, and throttle body. What should be my next move? I was thinking the coolant temp sensor since it goes fine after warming up. I noticed the wires have a big kink right before the sensor, would this cause those symptoms? Thanks.