slk 230 sudden power loss

Raul,

This could be many things from a blown catalytic converter (there's already another post in this NG today about that), a bad sensor, a clogged air filter, or fuel supply issue. Get the codes read from the OBD-II (the gas cap issue will cause a check-engine light, but I don't believe that it will cause the substantial power loss that you noted). This can be done for free at some auto parts stores, or perhaps you have a good independent MB mechanic nearby (in fact, you might find it much more cost effective to use an indepedent).

Josh

Drive it, if there's anything wrong the power lag will repeat itself.

You must present a shop with something better than this or you'll become another victim of "let's try this, oh that didn't fix it, well, then we'll install a new sdkhjfdgkjgfkj" - all at YOUR expense. This gets to be a painful game so don't play until you have specific symptoms to deliver to the shop.

Could be as simple as some marginal quality fuel.

hello, thanks for all your responses so far. i will take it to a local MB specialist and hopefully i will be able to get the codes. so far i have noted that the gas cap helped with the 'check engine' light but the power loss is still present and VERY noticeable. the oil light came on twice on my way home from work, it would clear as soon as i turned off the car and turned it back on...i'm gonna go check oil levels, but levels were fine few days ago.

"Danger, Will Robinson." (ok, I'm dating myself with that reference) Anyway, your oil light indicates pressure, not volume. Carefully take this car to a mechanic.

Josh

so, i take it this is a very bad sign? what does a problem with 'pressure' mean?

It could mean anything from your pressure relief valve being bad to your engine needing a rebuild (but I doubt it). What is odd is the "sudden" performance drop followed by the oil lamp. Engines don't tend to wear out suddenly. It's possible whatever is causing the performance drop is reducing your idle speed (I'm assuming that the oil lamp only comes on when the car is sitting in traffic) to the point that the pump is not moving a sufficient volume of oil.

Josh

I had that happen, and it was the fault of the fuel filter (Fram). It has a bypass, spring loaded, that gave out.... in my case it meant the oil wasn't being filtered.

cheers, guenter

Crazy enough...took it to my mechanic (very honest guy and very helpful) and he replaced the fuel filter.

He mentioned that the brand of gas I use also tends to affect performance. He asked me, "What kind (brand) of gas do you use?" I replied, "Chevron or 76 and on very rare occasion Shell" He recommended me switching to "76" as he has never had any problems with that brand and all his cars use it. He gave me examples of other clients and how a client switched back to shell after 2 months of his same recommendation and her Benz gave her a hard time again with one single use of Shell after fixing it.

Later that night I remembered that I had filled my tank the first and last with Shell and started giving me problems.

I switched to 76 ever since my car got the fuel filter replaced and now it is running like new ... except I still think it consumes too much gas per gallon.

Anyway, thank you all for your help. Raul