Greetings All.
I have a 2003 SLK 230. 85000 miles. It was running fine till the other day. I was pulling out of my driveway and the car stalled. It restarted however it was running rough. Then it would smooth out and run rough again. I connected my Maxi Check scan tool and found a P0340 code camshaft position sensor. Thinking I found the problem I replaced it. There was no change, and no codes were set after that part replacement.
So today I ran the car and the same lumpy idle. I will run smoothly then the idle will drop and almost stall. I did note that as it warmed up it seems to get worse. Start running rough then stall out. It does start back up. It will run very smoothly for a minute or two then start acting up.
I also checked the fuel pressure, it is a steady 50 Lbs. During the summer I replaced the K40 relay, filters, fluids, and spark plugs. The car has been wonderful to drive.
FUEL SYS A – CL-Fault
FUEL SYS B –
SHTFT1 – (-2.3)
LONGFT1 – (6.3)
O2S1 1 – (.775 V)
SHRTFT1 1 – (-3.9%)
O2S1 2 – (.0440 V )
SHTFT1 2 – (99.2%)

Can someone please help me to go in the right direction.

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2003 SLK 230 (85000)
1999 E300 Turbo Diesel (388,000)
1991 350SD Turbo Diesel (185,000)