2000 S model idle issues
 

Hey everyone. I've been having issues with my boxster. I keep getting the two codes saying that the mixture is lean, but yesterday something different happened. I was stopped at a light and the idle started dipping down like I was running out of fuel then shot up to 2000rpm for a second then came back down. I've already replaced the maf and aos and also checked the oil cap. Could it be the oxygen sensors going bad and trying to correct a problem that isn't there?

Hope this is some help even though it is an uneducated guess, but easy enough to check.
I would look to the fuel pump relay...you can feel if it is getting hot, plus you can jump it out (its right next to your foot) and you could have a failing fuel pump as well. You can hear a failing fuel pump sometimes.
Check for leaks on the replaced AOS, I had the issue with mine after AOS service and that was what was wrong. (I didn't get any codes on this, however)
I would think the oxygen sensors would send a code if they were failing, not sure. also, the o2 codes only indicate something is out of whack, doesn't mean "bad sensor"

When I first started having the codes pop up, I went ahead and replaced the aos. That solved it for a couple months then they came back so I replaced the maf. Same story. Ran fine for a couple months then the codes came back with another one saying that the idle rev was too high. I haven't heard any noise from the pump indicating that it's going out, but that doesn't mean anything. I've also had a fuel treatment done just in case the injectors were fouled up. The car only has 99k miles on it.

Please post the most recent codes...

Have you cleaned the throttle body? If not give this a try.

I have. I also took off the intake and cleaned it.

I'll have to do that after work. The batteries in my reader died and I have to get ones ones after I get off

Just a quick update. I replaced the oxygen sensors and it seemed to help, but now I have a new issue. The car is acting like it isn't getting enough gas when I take my foot off the gas peddle. As soon as I take it out of gear, the car shuts off as if I turned the key. No sputtering, just shuts off. When I turn the key again, it fires right up. I suspect either the fuel filter or fuel pressure regulator might be to blame. As always, your opinion is valued