95 C280,new plugs, good wires, OVP ok, still runs horrible

I am stumped now, I'v eput new plugs in the car, I didn't replace the ignition wires but they look good and I see no sparks when sprayed with a fine mist of water at night, the OVP sensor is the upgraded part #.
And the car is running progressivley worse. It used to run ok if you restarted the engine. now that only seem so work for a minute or so.
How do I go about retrieving the trouble codes for the car. Or is there other parts that should be replaced?
Any advice on what could be making the car run so bad? Please!

Thanks
Shawn

[Arthur Dalton]

Don't assume the OVP is Ok just cuz it is the new style.. they still go bad

When your car is running like crap, go tap the OVP with a few light taps with a screwdriver handle and see if the engine responds..

How is the harness ?
..and the mist trick does nothing to show the connectors under the coils that are notorious..

Tapping the OVP while the car is missing did get some response. Although only for a second or two. So does this mean that the OVP is bad?
When I take the cover off the OVP part of the board is discolored, looks almost burned. Can these be fixed or should I just replace it?

[Arthur Dalton]

Replace is best with HFM cars

..and what did you dp about the plug connectors under the coils?
..As you just changed plugs, I Do hope you took the advice of F8DC4..

[James L]

do like arthur dalton said and tap ovp with screwdriver while running crappy. on my w124 1993 i had an abs light, crappy idle and a/c. when i taped on old ovp it started to worked fine if only until next start up.

ordered a new ovp from www.*************** for $62 (KAE), no more abs light, runs great and a/c works.

Ok, I'm starting to loose my patients with this car. I put a new OVP relay in the car today, and still no difference. The one thing I haven't replaced is the spark plug connectors under the coils, which I will do later tonight or tomorrow. But the car is missing so bad that at times you can't accelorate from a dead stop because of the missing and backfireing.
The plug connectors are all that is left to replace from the list of things that usually cause these problems. According to the post I've recieved.
Is it possible that the plug connectors could cause the car to run as badly as it is running? When I looked at them they don't appear to look burnd or discolored.

[James L]

has the engine wiring harness been replaced/updated to the non-biodegradable one?

I don't know if the wireing harness has been replaced or not, I didn't get any records with the car. Can you tell the difference between the two by looking at them? The harness on the car right now dosn't looked cracked anywhere.

[Johnhef]

If your harness is hard as a rock or splitting anywhere else on the engine I'd suspect that. Look close at the plugs on the valves at the front of the head and at the two connectors on the thermostat housing. If still ok there, slice open one of the coverings to a coil (where it bends) and inspect the wires inside the covering for cracking.

Also don't rule that you might have a bad coil(s).