I purchased a L300 4 dr sedan today. It is a 2001 with 55,000 miles on it and had one owner. We bought it from a GM dealer and it was certified. Drove the car home (about 20 miles) and just a s we were getting off the free way, the Service Engine light come on. So I pull into my garage and get out my scanner and 2 codes pop up
P0171 and P0300
One is a misfire and the other is a lean condition
So I call my salesperson and tells me to bring it back. So I drive back and a mechanic is waiting in the driveway to greet me. He takes the car into a service bay for about 15 minutes. He comes out and tells me everything is OK and and that the SES light was due to the gas cap not being on all the way. So I say are you sure? He says yes and then I whip out my scanner out of my back pocket and tell him that the 2 codes that I got had nothing to do with the EVAP. He went into shock and I asked for my salesperson and the dealership manager. They assured me that it was taken care of and that if it comes back on, to bring it in. So off I go on my way home and I made a couple of stops, but after about 20-25 miles the SES light came back on. So I made an appointment for Tuesday morning.
What could be the problem?
Any ideas would be appreciated.
Jack