I just bought a 99 merc cougar that had the 2.5l svt engine swap. The car is overheating at idle and during take off in reg city driving. On the highway the car runs fine. The only way i can keep the vehicle from overheating is running the A/C. Which seems kinda odd cause doesnt it put more strain on the engine therefore making it work harder??? Ive changed the thermostat and the car ran fine for a little while but now its acting up again. CEL codes are basicly reporting EGR problems. I just bought a new Coolant switch and im going to switch it out, thinking maybe its going bad. The guy that sold me the car said that hes had it at the ford place and they told him that the car is not overheating. Something could be wrong with the ECU. I know more about working on an F/A-18 Fighter Jet then a car so im pretty much clueless. If anyone knows any suggestions as to what this could be, would be much appreciated. Thanks!!