99 E320 Wagon is stalling out when it is cold. Check engine light was on and had a diagnostics ran. It noted the O2 Sensor. We changed it, the check engine light is off, and the car is still stalling out when cold. Check engine light has not come back on. When it stalls I let it rest for a few minutes and restart. It restarts but if I let still idle it will stall again. When the car is at normal temperature it does not stall.

Any suggestions? We thought maybe to replace to other O2 Sensor too...

 

the O2 sensors have nothing to do w your stalling car. if u would unplug every O2 sensor then ur engine should run in open loop.
if u couldn't read any other code than the O2 sensor then try to replace the fuel pump relay. that could do this and cannot set a code.

 

It might be best to say nothing.
His engine runs when warmed up.It is not the FPR.It stalls cold.
Check coolant temp sensor
Check pending codes in the obd
If you don't have a real time scanner get it on an sds scanner and run the coolant temp sensor values,Cps values,Cat function,etc.They often will not show a code.
Fuel pump relay failure would show a code and how would the engine run with no fuel,anyway?

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Your problem is very simple. I believe if you replace crankshaft position sensor, it will improve 100%. I have 99ML320 with missfire in multiple cylinders and Star manual calls for CPS right away. I was blaming plugs, wires and coils witch had nothing to do with it. Stalling is a common symptom for bad crank sensor. Good luck!

 

Mine did what you describe and it was the MAF. Random multiple misfire codes and bank one lean it said I think It would start run fast idle and stall.