Hard cold starting, rough idle 89 300E
 

Hard cold starting, rough idle 89 300E
Hi Guys, It seems my 300 is starting to fall apart.
Which is surprising as I try to really stay on top of maintance. Right now it dosent want to cold start and idles rough while in gear.
History,
Everything was running great until it overheated one day, I began changing parts (the radiator was changed about months before), anyways I changed out the thermostat, hoses, waterpump, heater valve/pump. Its still using water possibly from a crack in the plasitc water tank (thats the least of the problems).
Soon after it began idling rough (for no particular reason). Oil and water are all clean and clear.
I figured 60,000 miles since rotor and cap hopeing for an easy fix. After new cap, rotor, plugs no change.
Injectors were changed new 60,000 miles (still hav originals in boxes that ran like new).
Question where do i start?
I changed out the start relay (little black box by battery) and OVP relay about 2 months ago as preventative maintance. Should I put the old ones back in??
Could an accumulator cause rough Idle?
I'm open to reccomendations,
Thanks,
Alex
89 300E 197,000

Does anybody know what this could be?
JAlex