nabc43

Hi guys,

I have a 2003 S500 with about 60,000 miles on it, starting a few weeks ago every once in a while when I pull up to a traffic light the engine will start running rough, if i do not put it in neutral and give it a little gas it will actually stall out. It does not happen every time and does not happen that often, it could happen at one light and 2 minutes later at the next light it will be fine.

The Check Engine light did come on once and stayed on for a couple days and then went out, i always thought once it came on it would not go off until it was reset.

At speed it runs great, i have actually driven it twice from Ohio to NC since the problem started with no issues....I have run Fuel Injector cleaner through the system but can't really tell a difference.

Any ideas????

Thanks

Nick

Supergenius40

Its either electrical (spark), air or fuel. I would start at air first. Look at your intake filters and clean your MAF. The dirty MAF will cause an engine fault (check engine light). My car would idle rough and change gears rough randomly. I bought a can of MAF cleaner and cleaned the sensor. The car drove much better and the light fault cleared. Advance sells the can for about $9.00. You'll need to pull the filter cover to get to the MAF so, two birds with one stone.

Trinsoca

Also check the EGR (Exhaust Gas Recirculating) valve. If it is sticking it will cause a rough idle also.