when I start engine it surges bad. when I accelerate up to half throttle its okay, but more than that,it falls flat on its face and misses and backfires through the exhaust like its real lean.i unhooked the iac to stop the surge,but it wont idle cold. the weirdest thing is that it gets worse when its below 45 degrees. as the temp warms 50 to 60,it starts running good again. Ive replaced the mass air flow,map sensor,coil and coil wire,and the tps. Ive checked for vacuum leaks and I replaced the fuel pressure reg and the ignition module about a year ago. the engine now has 222500 miles and still runs strong except for this.