please excuse me, but i also have tha same problem. I have changed spark plugs and wires,rotor pin,replaced air filter with a K&N. My o2 sens comes on only untill i start moveing and then the light gose off. I have 178000ml on my 1987 420 SEL. I used BOSH wires and plugs (not the best) from what i have been reading on this site, but i'm still learning about these cars. Any insight would be very helpful and no, i have not had the timeing chain done yet!