I have a 1992 600sel with 72K miles on it. I have replaced both engine wiring harnesses at under 50k miles.
Now I'd like some direction--the Check Engine light is on, I have a rough idle and loss of power both from a stand still and while cruising. Gas consumption is up also, and I have no local mechanic that can troubleshoot the problem.
I've replaced one mass air flow sensor (at 45K miles).

Can someone with knowledge recommend what I should look at checking/replacing ? Thanks in advance.