Q: 2003 Mitsubishi Outlander XLS: fixed oil leak, replaced gaskets on exhaust, intake, and cyclinder head. Car now idles rough/stalls

asked by on September 04, 2017

Car had oil leak and code P0420. After cleaning the vehicle of Red RTV on all gaskets and replaced with new (exhaust, intake, cylinder head, exhaust pipe, throttle body gaskets; plus new thermostat, new spark plugs, new wires, changed oil & filter, flushed radiator, new coolant, new O2 sensors, & serpentine belt).

After finally cleaning oil spills on all parts and running vehicle to check for leaks no leaks exist. However, unless it is cold started the car runs on very low idle & eventually stalls.

When I put my OBDII scanner I acquire no codes. However, the following have come up the course of the month I have been working on vehicle:

P0102 P0107 P0113 P0335 P0420 P0506 P0507

As of today when I checked again none of these codes came up. The only ones I cleared a couple months ago were P0420 and possibly 1 other one but don't recall. The rest I never erased but they did not come up.

Is there a procedure for the car relearning proper idling?

My car has 99999 miles.
My car has an automatic transmission.

It is possible that you could have a vacuum leak. I would recommend having your vehicle smoke tested to determine where the source of the leak is. Perhaps the intake gaskets are not properly seared causing an incorrect air fuel mixture.

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