My '01 W210 4matic wagon w/155k sometimes goes into what I think is a 'limp home' mode when flooring the accelerator to pass, the throttle becomes very lazy and unresponsive though it will drive at highway speeds. Turning off and restarting restores it to normal function. There are no check engine lights or other indications of problems like erratic gauges, unsual shifting or misfiring. Maybe I'm nuts but I think it's more of a problem when the weather is colder, now that it's getting hot as hades around here again it seems to occur less often. This has been going on for some time now but as I seldom do much serious passing at full-cry (wagon w/ kids, etc) it hasn't been a big issue. Any thoughts?

Sorry if this has been talked to death, I searched and didn't find much...