Check engine light came on a week ago. Stalling when coming to a stop and idles very low. Mechanic reset the code and gave me some instructions and said the car would have to relearn to idle. Have tried turning car on without starting engine and waiting 2 minutes, start engine and let car warm up, then drive and it seems to do ok. Still idles low. When I stop the car and come back to drive again with engine still warm, stalls twice as much and low idle is worse than on the first drive. Getting frustrated. Any advice.