Yet another check engine light question! I have a '95 E320 and I get the check engine light after I have driven for some time at around 140kmh. I have cleaned the tube, replaced the EGR valve (that's the fault I get from the OBD)

If I don't drive that fast the light stays off, the last time for almost 4,000 kms. Dealer and indy's don't have a clue. Any ideas?