1986 300e running rough when stopped - and timing chain replacement

[sranauta]

Hello

I have recently replaced the fuel pump relay and the overload relay. The cover on the other relay next to the fuel pump relay (what is that for by the way?)had come loose and the car was failing to start. I sealed it with some silicone sealant and replaced it and all seemed well except now idle speed when in Drive but stopped is just a touch above 500 and a bit erratic. If I switch off the a/c it goes up a bit and runs a bit smoother.

This model does not have an EGR valve.

Any suggestions please

Also I have replaced the timing chain tensioner but although slightly reduced I still get timing chain noise. I have obtained a new timing chain and tensioner guide rail and upper cover rubber seal. Should I be replacing the inner and outer timing chain guide rails, and sprockets too ?

Many thanks