I got the CEL on my 2000 ML430 and took it to my mechanic. He read the the code as, Fuel Trim Malfunction, and told me he thought it may be the Catalytic Converter but can't be sure. He told me to take the car to the dealer for diagnosis. When I left the shop, I started gunning the engine, the CEL went off!! This is the second time CEL has turned off after I gunned the engine several times. The car seems to run well except I feel the power has diminished since this CEL has showed up. Any ideas?