Car dies and or runs rough after 10-15 min

[88260e]

So Ive posted on this subject before still chasing the same problem??? So my 92 400e for over a year now will randomly act crazy!!! The more it sits the more it seems to happen? After a short drive or sitting at idle the car will buck,stumble,misfire,and sometimes die. If it does die it will not restart unless you weight an hour then it will start up fine an run fine??? The car will go sometimes a month or two without a stumble and sometimes it will happen daily. New this year, rotors, caps, wires, plugs, air filters, last year CPS, FPR, Coils, fuel pump relay, battery, alternator, starter, upper harness. ETA was sent out and bench tested, all vacuum hoses are new all breather hoses are new. The mechanics at the shop I worked at couldn't find the problem, brought it to another shop Master Merc Tech, we thought he found the problem! The ends on the new wires to the coil seemed loose, pressed on but not twisted on so we tightened them and the car seemed fine for a month then it went stupid again??? I'm lost??? someone mentioned to disconnect the aftermarket alarm to see if that helps so going to try that ASAP. But anyone out there run in to this problem before cuz it's driving me crazy. Sorry if you've read other posts about this problem before, and I'm repeating myself but I'm S O L