I have a 89 SC with 45k original on it, she has been sitting for awhile and it seems like everything is going bad from lack of driving. Just last month I replaced the MAF, IAC, bolth o2 sensors, and plugs, wires. because it was having trouble at idle and it would die out every now and then at a light. It was running better after the tune up but it still has a rough idle and makes a putting sound out of the exhaust. I was just going to live with that but in the last couple days while driving it the idle would start bouncing up and down and when you pushed the gas it would drive like you were pushing the pedal up and down. The only way to get it to stop doing it was to turn the car off and restart it. It is really hard to restart after it happens also. and when it does finally start after 3 or 4 turns it runs great but the tach will not work for about 2 minutes. It has done the exact same thing 3 times now with no engine light! ANY IDEAS??