Hello,

I have an '05 Vanden Plas with about 151,500 on the odometer.

Car is running beautifully BUT---at normal idle (about 600rpms) when warm it will drop to 200 or 300 rpms and feel like it is going to stall. ALSO--after driving at temp I will make a stop somewhere for ten minutes or so. When starting car back up it will run very, very rough and then the check engine light comes on...I rev engine and all is good after that...check engine light comes back to misfire codes...

I am assuming I should start with replacing plugs?? I recently purchased vehicle so am not sure when they were changed, if at all. If I am on the right track please let me know the best plugs to purchase.

Thank you

 

If the MIL is on, what codes are stored in the system?

The fuel pressure should also be checked to determine if the pump is failing.

Changing the spark plugs, air and fuel filters is a good place to start. If there is oil present in the spark plug wells, the cam cover gaskets and spark plug boss seals should be replaced.

 

Thank you very much

 

And clean the throttle body with carb cleaner on a rag.

 

Smells like fuel delivery issue to me - there is a shrader fuel port you can hook up a fuel pressure gauge - make sure you get the right pressure when the vehicle is idling and that the pressure stays put after you switch off the vehicle. I would do that first before anything else.