My '91 190E 2.3 has changed how its running recently. Perhaps someone has some suggestions. First the fast idle speed dropped from 1250 to 1000 rpm. Not a big deal, just different. The idle is still quite smooth. Also, there is quite a hesitation on acceleration at low engine speed. Sometimes its much worse than others. My first inclination is that the fuel pump is getting weak or the accumulator isn't holding pressure. I will check these soon. New plugs, distributor cap, fuel filter, etc quite a while prior to problems developing. This summer when it was very hot, (110F) the engine would die at idle. No problem with that now that it's cool. Any thoughts??
Thanks in advance
'91 190E 2.3