2000 Boxster Smoking issue
 

I've got a 2000 Boxster S that recently started to have a rough idle and fuel mileage dropped off some, not much but about 10-15 miles less per tank. I puT a bottle of Berrymans B12 Chemtool in a full tank of fuel to see if that would help clear up the rough idle. I thought maybe a fuel injector was dirty. The rough idle cleared up after just a few miles of driving. Thought the problem was fixed. The next morning when I went out o go to the gym, I started the car and huge clouds of white smoke came out of the exhaust. Smoke went away after the car warmed up. I spent about two hours at the gym started the car, again big clouds of white smoke. Got on the interstate to go home. Accelerated again huge clouds of smoke. Not continuous just during acceleration. Check engine light came on, flashed about 5 times the went steady. It's till on. Took the car to O'Reillys to have the code read but their machine wouldn't recognize the car. We don't have a Porschedealer here. Any ideas?? I had one mechanic tEll me to run that tank of gas out of the car and fill with fresh 93 octane.

We need more info, i.e. mileage, how long have you had it? Search AOS to start. A bad AOS can cause serious engine damage. Drive it sparingly, until you sort it out.

+1 bad AOS. I would not drive it at all at this point as serious damage can occur due to hydrolock from liquid oil in the cylinders. If you can remove the tube to the intake from the AOS. Probably full of oil. Good Luck

Classic AOS symptoms. As Rex says, you don't want to drive your Box if it has a bad AOS. Worst case is you can hydro lock your engine which results in a bent or broken rod.

Have you checked your oil level? A bad AOS lets oil into the combustion chambers, causing all your symptoms. Remember to check it after replacing the AOS, as it will probably be low.

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Fuel additives can create smoke but in a limited amount.

If the smoke clouds look like your engine blew up or a James Bond 007 smoke screen, then its most likely your AOS.

Ok folks I'm fairly new to the Porsche world. What is the AOS? Where is it? Car has 88k miles. Was running great until 2 days ago. Oil level has not diminished. I held a white paper towel up to the exhaust pipe and there is no oily residue.

Sorry for being the dumbass here! I figured out what the AOS is. I'll get it replaced next week.

Luckily it's a pretty cheap fix. I would check the MAF and throttle body as well to see if they need to be cleaned at all. My car had a rough idle as well that was symptomatic of a bad AOS and MAF.