I bought a 2003 Stratus 2.4 DOHC and after diagnisis I found that one of the Exhaust Valves was cracked. I proceeded to repair this issue correctly by having the head rebuilt by a creditable shop. I installed a new timing belt/water pump assembly and regasketed every gasket that was possible during this repair. The shop had to shave .007 of the head to get it flat again. After reassembly the car ran pretty good but had a speradic idle issue then it gradually got worse but the car runs fine while driving. I had investigated all the normals, compression, vacuum leaks, cam timing and all check out. Normal compression is usually 165-180 but my car has 205-210 resulting from the head work. I have decided to investigate the possibility that the bump in compression is causing my issue. I have just this last tank started running a higher octane but doesnt help much. Can anyone give any advice as to what I may try to compensate for the rise in compression. Im not totally sure in higher compresion would make the vehicle run lean or rich but I am curious if a different heat range plug may help a litle. Thanks in advance