I own a 91 MB 560 SEC. I've been having a few problems I'm hoping someone on here can help me with. As of now, I am having trouble getting the car to start. The only time it starts up fine is when it was already running within the past 2-3 hours. I thought it could be the battery, so I brought it into Autozone. They charged and tested it for me. Seemed fine. Bought all new premium spark plugs, didn't help. In fact, after installing the new spark plugs my car seems to shake more and have worse acceleration. So I figure that it isn't running on all the cyclinders, which is weird. Another problem I am having is with the idle control valve. It's pretty much shot. The car revs up to 1000-1500 rpm in park and nuetral, but in drive it drops back down. I think this is seriously ****ing up my tranny, since it slams into drive/reverse. Yet another issue I'm having is shifting in between gears. When it shifts from first to second theres a delay where it makes a loud noise and stops accelerating till it reaches second gear. If anyone can help me with any of these problems I am having, I would greatly appreciate it.