99 slk230 sudden power loss
 

The car starts fine, no indicator lights on panel. On three separate consecutive occassions in the last week I drove the car approximately 9 miles and would experience sudden power loss, this is dangerous in rush hour traffic on the highway. I tried starting it immediately afterwards but it would only crank. Then after waiting 1-2 hours it would start and I could I drive it indefinitely the rest of the day but the next morning, after an overnight rest it would have sudden power loss again after about 9 miles. I have replace the K40 sensor but that did not resolve the problem. What could it be :confused: