Difficult starting when warm/rough idling
Thread Starter
Junior Member
Joined: Aug 2013
Posts: 65
Likes: 8
From: Fallbrook, California, USA
1997 Mercedes S420
Difficult starting when warm/rough idling
Vehicle is a 1997 S420 with 255,419 miles located in So California. I am no mechanic even though I have a lot of tools. 
I will not attempt to resolve this on my own but would like to know what I might expect from a mechanic. I am on the hunt for a mechanic in Northern San Diego County and would appreciate referrals based on experience.
When I start the vehicle for the first time each day it starts in perhaps two rotations. However, as soon as it warms up to operating temperature the idle becomes rough and there is what feels like a miss in the engine.
All subsequent attempts to start the vehicle that day require cranking the starter motor at least twice and sometimes three times and the idle continues to be rough.
Other than this situation the vehicle is in great shape cosmetically and mechanically and drives like a dream with plenty of power when needed and no hesitation in the engine at all.
Any thoughts sincerely appreciated. Thank you.
I will not attempt to resolve this on my own but would like to know what I might expect from a mechanic. I am on the hunt for a mechanic in Northern San Diego County and would appreciate referrals based on experience.When I start the vehicle for the first time each day it starts in perhaps two rotations. However, as soon as it warms up to operating temperature the idle becomes rough and there is what feels like a miss in the engine.
All subsequent attempts to start the vehicle that day require cranking the starter motor at least twice and sometimes three times and the idle continues to be rough.
Other than this situation the vehicle is in great shape cosmetically and mechanically and drives like a dream with plenty of power when needed and no hesitation in the engine at all.
Any thoughts sincerely appreciated. Thank you.
