[dave3999]

I have a 95 Deville, 4.9 with a rough idle and stalling problem. Fuel pressure tests fine, vacume can be low (tested as high as 18 and steady, as low as 12 and steady. Current Codes are P053 and p012, sometimes history, sometimes current. Sounds like timing is off (knocks under a load), gettinf ISC code as well on and off. Have been through 3 ISC motors, replaced Hall effect swithc, ECM and PCM. New cap, rotor and coil (old looked awful). Sprayed starting fluid around intake, no noticable increase in RPM, Problem is much worse when warm. I'm thinking pick up coil, any suggestions?