Kinda stumped on this one...
 

So my 2000 Boxster has been running okay out of winter storage the last few weeks. But this past week is was not running that great... I pulled a 1126 code... could be vac leak, 02, MAF (I replaced the AOS two years ago and it shows now symptoms of that being bad)...
It didn't feel that "peppy"
Anyway, went to start it today to look for vac leaks and its dead. The key was not in it either (done that before). The battery is being load tested right now.

Wondering if the loss of power could be from a bad battery? I read mixed opinions on that.

I guess maybe I have two problems? A bad battery AND a vac leak, 02 or MAF problem?

All this while I'm rebuilding the top end of my daily. I blew a timing belt on my 1.8 Audi daily:( So that car is down while I replace the valves etc...

So NOT a good car week:( Was depending on the Box and now not sure...

wow, BUMMER times 2:(

The ECU will change some parameters in some situations based on battery voltage. For example, the ECU will enrich the mixture a bit at startup if low battery voltage is detected. The logic is that low battery voltage means that the starter may not crank as fast and the slightly rich mixture will help the slow turning engine to start. I'd have to look at my fuel injection books to recall exactly what other situations battery voltage affects the engine control.

I had the same code and worked all the angles. Ended up being a bad MAF. I bough a Bosch unit and it cleared everything up.

I am going to guess the battery is a separate issue and not related to your code. I hope I am right. Good luck and keep us posted.

Did you use a battery maintainer during winter hibernation?

Replace the battery first.....one that is dying slowly will make the car act peculiar.

Ok, got out my handy Bosch Fuel Injection and Engine Management book (everyone has of these, right?) and the ECU will also slightly alter the ignition timing based on battery voltage. The logic is that lower battery voltage will not charge the coil packs as quickly. The goal is to maintain constant current in the coil packs so as not to overheat them.

With all of this being said, P1126 is oxygen sensing adaptation range 1 (cyls. 4-6) at enrichment limit. I doubt that this code is the result of a bad battery alone, so its probably two separate problems. But go the easy route and replace the battery and see if that fixes the problem. These integrated engine management systems can create somewhat strange symptoms based on simple problems. If not, then proceed to look for a vacuum leak, bad MAF, etc.

Thanks thstone!

I did have a bad battery:( So that is fixed! I had my old one load tested and it was not taking a charge... and you are correct as far as that not having anything to do with the 1126 code...

I just started a new thread regarding my AOS... I should have just updated this thread instead of starting a new one...:(

http://986forum.com/forums/general-discussions/45279-2nd-bad-aos-continued-thread-yesterday.html