to make a long story as short as possible I picked up a 1999 CLK430 and had the MB dealer do the inspection everything came back fine. The car had the mass air sensor replaced about 4 months ago by the same dealer for the previous owner. About a week or two after I purchased it I noticed that when I punch the gas real hard the car was basically falling on its face and accelerating real slow with the RPM's at about 3500 rising very slowly. I took it to the a different MB dealer (where I live) and I had them service the tranny to be safe. It still ran bad when hitting the gas hard so I took it back again to the same dealer they ran some more test rest the adoptions and said the only thing that came back with any problems was the crankshaft positions sensor instead of paying another $300 to have them do it, I ordered it and replaced it myself a couple weeks later but since they had re-set everything it ran great for a week in between. Before I replaced the CPS I did a battery reset at my house instead of going back to the dealer and that fixed it for another week or so. Right before I actually did replace the CPS it started doing the same thing again. This time I took the car to a very well know independent MB mechanic called MBI here in Portland OR. They did all the test they could said all the adaptions where almost perfect but did say that the CPS had not been reset since I did it myself. They cleared the ME (Engine Electronic Control Module) to the initial factory settings. And of course the car runs perfect again. They said that if the problem comes back then they are pointing to-wards a new computer. They said I could get a used one and send it to Beckman Technologies in N. Carolina and they could unlock it for me. I called them and spoke to a gentlemen and he really doesn't think I have a bad computer he said these computers are always mis-diagnosed and they are a very reliable computer. So right now I'm stuck and really hoping the problem doesn't come back and something MBI did get fixed but if someone has any ideas as to what the problem could be please please help me out here. Oh yeah car runs perfect all the time if you don't punch the gas, I only know there is a problem when I step on it.
Thanks so much

Benz ecu's are relatively reliable. I'd be looking at possibly bad MAF - even though it was replaced, coolant temp sensor, crank sensor, TPS or even O2 sensor. Has anyone checked those sensor values ?

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Sharing my partner's 2012 Forte 5dr SX til I find my next 123 or 126..
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Do I miss being a service advisor ???

That is also symptomatic of a cracked plenum air intake...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

That too...

__________________
Sharing my partner's 2012 Forte 5dr SX til I find my next 123 or 126..
-
Do I miss being a service advisor ???

They said all the values where good, he said they where almost perfect. According to their computers my car should be running great???

Has the fuel filter ever been replaced?

That did cross my mind but the weird part is it runs great when you reset the car?? It seems if it was the fuel filter it would always run bad since that is more mechanical than electric?