Lambda

93 190E with 2.3 eng. has rough idle. Replaced plugs and one resistor tip, which smoothed idle a little. I then decided to check voltage at the diagnostic socket. With key on engine off I am only getting 1.83 volts. With engine running I'm getting 13.85 volts. Duty cycle gives me OL on my DVM. I decided to replace the over voltage relay, which didn't change my readings. The literature I have, says there should be 2.5-5.0 volts koeo and should be around 6.5 volts with engine running. There are no faults stored when checked with scanner. What else could cause these symptoms if its not the OVP? Any suggestions are appreciated.