1989 230e had hard cold and hot starts check this before spending a lot cash on parts you may not need

remove air cleaner
check cross bar on top of sencer plate remove from vehicle and see
if it is bent if so the vehicle has had a back fire
try to strightern crossbar (vise)etc
now check if sencer plate is coming all the way back if not
loosern 10 mil bolt and adjust sencer plate and moke sure there is no binding once you have done that tighten 10 mil bolt and refit crossbar
start vehicle if it runs ok now adjust mixture run vehicle until it is hot
remove black diaignos cap and check the voltage with amultimeter from
number three and to earth the reading should be 6.9 to 7.2 mixture adjust
all done refit air cleaner .