126 rough idle at times and soft bouncy ride
 

new to me, 1991 560sel with 81,xxx miles

I am 3 rd owner, not much on service history on vehicle sadly.

problem one,

at times, she runs / drives and idles great, at times a sputtering / hiccup on cruising and at idle..... electrical or fuel side ya think ??

problem two

a very soft / spongy ride. had all the hydraulic lines replaced recently , the nitro accumulators too. that solved the saggy rear.

I m guessing front shocks are spent , any symptoms on failed rear shocks ?

thanks for all the help

All underhood rubber probably rotted after nearly 30 years of service for your idle.

Your crap ride... from front or rear? Rear could be SLS valve bad, leaking shock, leaking high side hose, or leaking pump. Fun times there for you. Front? Probably needs a rebuild as rubber degrades.

gathering up all the parts for new rear shocks and rubber washers on top of springs, new front shocks, brakes as a might as well while everything is apart.

fuel filter, oil change, wires and plugs and see where I m at then.

next of which I m sure will be injectors.. and all the related orings.

I think engine timing parts are plastic,better replace too,so that fine motor will last.Flex disk,and service trans.Radiator maybe rotted alowing ATF to mix with coolant.

thank you oldsinner for your service

and thanks for the reminder of flex discs and timing chain parts. flex discs most likely reason for the little driveline growl while driving.

Check for vacuum leaks with a shot of MAF sensor cleaner or similar. Shoot randomly around the engine bay at idle and listen for a change. If it changes at all, start working on the components on that area to find the leak. My 300TE had three injector seals sucking air through. Also, check the EHA for leaks. If it's damp or you smell fuel with the hood open, replace it. It's expensive, but it is critical to proper injection system function. Also, replace the O2 sensor(s?) if it hasn't been done.