I purchased my 2002 Dodge Stratus SE Sedan 4-door 2.7 little over a month ago it was having some problems with ignition misfire and what not. Some problems I notice is when its on defrost the engine itself turns off, the rpm shoots up to about 1 to 2,000 for a bit and when I drive on the speed way then slow down there is a jerk sometimes. I recently got the MAP sensors replaced, brake pads and rotors replaced, oil changed and engine tuneup. The error code I get from Autozone is po172 one of the reps indicated it could be because of my engine computer and need to be replaced, any other opinions on this?