Over time my 1994 E320 Sedan seems to have lost power. The mileage is 152,000. I recently replaced the engine wiring harness due to catastrophic failure. The repair went well, and should not be part of the problem.

If I didn't know any better, I'd swearthe enginewas being 'slightly strangled' for lack of a better term. Nothing wrong really, but, like myself, just slowing down.

The engine light used to come on from time to time, but not since the harness replacement.

The exhaust is original. It recently took on a rumble, so that it sounds more like a 1971 280 SE. But the power seems to have been declining over a longer period. Say, over the last 30K.

The transmission fluid has not been changed in a long, LONG time, and shifts can be a bit rough, with winter operation when cold, a bit sluggish. I mention only because I question whether or not it could be complicit.

Without getting too long winded here, I was also advised that sometimes, if the transmission fluid hasn't been changed in a long, LONG time, it's better not to change it at all.

I do have platinum plugs in the car right now, and have heard it's a big no-no. But I had resister plugs in it recently, and they performed no better.

Any experiencedadvice on what I might look at would be most appreciated.

Mark