Mercedes C230 runs rough, then smooth, then rough

GreasyKnucklesGuy
Sat, 27 Jun 2015 15:41:35 +0000
Maintenance/Repairs

I’ve got a merc C230 Kompressor that has 174k miles on it. The car typically runs really well and is not underpowered or anything. Last weekend I took a road trip that was 400 miles or so. The car did fine for the first 300 miles but then began running rough and was underpowered. Was acting like there was a fouled plug. I pulled over and stopped the car where it sat for about 5 mins. When I restarted the car, it was back to normal, with a smooth idle and not underpowered. It ran fine for about 30 mins and then began running rough and underpowered. I find that when it starts running rough, if I stop the car and turn it all the way off for at least 60 seconds, then when i turn it back on it will operate normally again for a bit. This also only seems to be happening when its really hot weather, 90 degrees F or higher. Any ideas?

9 posts - 6 participants