L300 Purchased today...

[jackfoxx]

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

[ksion15]

possible, and i mean possible, mass air flow sensor or fuel pump. not at all certain without looking at it myself. also could be a vacuum leak. like i said, not a sure thing without looking at it myself. but, i can say this, if it is the same codes, with no evap codes, i would say they're full of it. gas caps usually set either a P0442 or P0440.

[jackfoxx]

Thanks for the reply...

Well here is the latest.
SES light came on the other day after the dealer claimed they fixed it and scanned it and came up with the same 2 codes P0171 and P0300

Took it back to the dealer this morning and they kept the car for about 2 hours. After they brought the car out they told me it was a vacuum line was leaking causing the SES light. I called BS on the guy and asked them to check into the MAF sensor as many of you suggested. He told me that those codes had nothing to do with the MAF sensor.

Left the dealer and drove around town (about 75 miles) and the SES light came back on. Scanned it and P0171 and P0300 keep showing up. Taking the car back to the dealer later in the week. I have printed out some information regarding the 2 codes and I will hand them to the service writer when I give them the car. Been researching the California Lemon Law regarding used cars...might just have to go there, dont really want to, but these people are pissing me off.

Need some suggestions on how to proceed...getting very frustrated.

Jack

PS.Some one on the Saturnfans.com board mentioned that there might be TSB's for these codes....know where I can get them at?

Thank You