Serious knocking/pinging/pre-detonation when accelerating after every shift

All of a sudden this has happened. Immediately when I give it gas after every shift there is a 1-2 second engine knock, ping....whatever you want to refer to it as, but all I know is that it is NOT a good sound. I thought our cars had knock sensors that instantly corrected and stopped this. Also for the past month every cold start the car barely idles at 200 rpm's or so and if I touch the gas pedal even very lightly the engines stalls. Just so you all know I use 93 octane from same station. Mobil 1 0W-40 clean and right at the mark. 8700 miles on odometer. At 7000 miles installed a Fabspeed cold air intake with BMC filter. There was no sign of oil or over oiling present on the filter. Thanks everyone

nothing?? no ideas anyone ?

Check for vaccum leak.

DID THIS START RIGHT AFTER THE AIR INTAKE INSTALL?ARE YOU GETTING A CEL?

WHERE IN NC?

I am in Charlotte. How can I check for vaccum leak...or does dealer do this? And I have no CEL illuminated, also I do not remember hearing and pinging or acceleration knocking right after install of Fabspeed BUT I have had cold start problems pretty much from the beginning of installing the cold air kit.

i also notice a pinging noise everytime i accelerate.. i thought something was maybe loose.. sounds like metal rods knocking around.. could it be engine knocking i'm hearing?? not used to listening for knocking sound coming from an engine behind me.. LOL i have a MY03 996 cab

Is 93 Octane the right fuel? In Australia I use premium unleaded which has an octane rating of 98.

yeah, i use bp ultimate 98 as well.. best fuel u can get in australia maybe its not the engine knocking.. i just got back from a drive and the sound is gone.. it comes and goes.. so annoying! i think the next car i get will be a GT... hmmmmmmm bentley continental... hmmmmmm

Maybe you got a tank of bad gas (wrong octane) - it's not beyond the realm of possibility that a fuel delivery got put into the wrong tank. I'd take the car to a dealer immediately.

That was my thought too......A bad tank of gas.

I have been told time and time again that most 996 engines develop this sound once they hit about 15,000 KMs. Apparently, it's all thr Variocam gearing and hydraulics causing the timing chains to chatter. It does sound exactly like detonation. I have spoken to two dealers about this and have been told this by both of them. It is normal and some engines do it more than others.

If it is true predetonation you might want to take it in. Pinging can destroy cylinders.

What about reinstalling the stock airbox to see if the problem goes away?

I would get rid of that airbox...and either drain your gas, or fill it up with a different brand of gas. I use Chevron out west...more expensive, but it's good gas. The best we get out here is 91, so go with some high grade and see if that works. I think you got bad gas.

If you suspect that it's bad gas, you might want to try a bottle or two of gasline water remover. Usually a dollar or two a bottle at an auto parts store. (A similar thing happened to a friend of mine. Her car would stall and was difficult to start because of watered down gas and totally cured by the water remover.)

I would be surprised if the car would idle at 200 rpm, that is prox 450 rpm below spec. A vaccum leak would cause a high idle, not a low one. Pinging (predetonation) is caused by either too lean a mixture, or too low an octane rating (for the engine operating conditions). Oil in the fuel (bad rings or valve seals) can cause oil in the cylinders which can be a cause for pre-detonation. The combination of predet and low idle may be an ignition problem. Perhaps start your diagnosos by checking your wires to the coils and your plug wires.........

I seem to remember quite some time ago reading about problems Boxster owners were expiriencing with after market intakes where by the MAF (I *think* mass airflow sensor) would get fouled up with oil somehow and cause poor performance. Since the engines are somewhat the same this might be worth checking. Either way I think going back to the stock airbox and a visit to the dealer immediately would be your best bet. Whatever it is it can't be good for your car.

Well dealer seems to think bad gas as well but that is just a verbal call at this point. Later this week they are getting it in and hooking her up to see what the read out says. I will keep you all informed.