Date registered: Dec 1998
Mentioned: 0 Post(s)
Quoted: 2 Post(s)
Re: Rough idle at operating temperature
Hey, I am having the same problem with my 86 420 with 165000 on it. Mine is more intermittent though. Sometimes it will shake like a cammed out Chevy and other times it will be a sewing machine. When I took it to the dealer, they said that my cylinders were getting starved because the fuel system is dirty from age. But it sounds like to me you've about had the whole system replaced!!! I was thinking about getting the injectors done, but from what you said, I'm not so sure anymore if it doesn't do anything. However...one mechanic told me that W126 V8s love to foul plugs if they are kept under 3000 rpm for a long time(ie city driving). So what I am going to do for starters is put Bosch Platinum 4 plugs in it, Jacobs 'performance' plug wires, and a Jacobs ignition amplifier which supposedly gives it a spark that is 1600% more powerful than stock. So I am hoping that that will smooth it out a little. Good luck and I will be following this post for any other info.