Please help! 987.1 Cayman S, getting low oil pressure and low to very high idle

I am new to this forum I'm just really hoping someone can help me as I've gone to two shops already over an issue with the low oil pressure light coming on in my 2007 Cayman S . I had the pressure sensor replaced twice after the Porsche dealership said it was the sensor after already replacing it a month earlier, and yet it wasn't the issue. It only comes on after its warmed up and when at a stop or coming to a stop at idle. Once gas is applied it immediately goes away and comes back if I don't continue to tap the gas or leave the weight of my foot on the Pedal. Now all of a sudden my idle after warming up will increase by itself to 1200-1300 rpm until the check engine light comes on and gives a code "air idle control system RPM higher then expected" or sometimes get "system to lean at idle bank 1 and/or 2". Once code it cleared the idle drops back down so low it almost stalls or does with the low oil pressure light popping back on. After about 15 minutes of driving the idle will begin to increase by itself again to 1200-1300 RPM's MAF & Throttle Body cleaned twice, and have the IPD plenum and GT3 TB with flash tune. Any help or assistance would be greatly appreciated. Thank you

First, read about installing either a mechanical or electronic oil pressure gauge that can be read while under way. Second add a oil temperature gauge. Then check the vacuum hose from the AOS to the intake throttle body. This vacuum hose, if rubber gets oil socked and my develop slight air leakage or collapse and cause a vacuum blockage. If indeed you have low oil pressure, I would switch to a 5W50 race type oil that has higher viscosity and film strengh that prevents cylinder walls and rod bearings from scoring or scaring. I would use Motul 300V power 5W50 and change it every 4000 miles. Its expensive, but your engine is even more expensive if you develop either bore scoring or rod bearing failure from low oil pressure. flat 6 innovation, Jake Raby has free videos that explains in depth why these issues happen to the M97 motors. Once a oil pressure gauge is installed, you will notice that stopping and turning with higher g forces after the oil is hot produces very low oil pressure. This is worse than simply idling. You might have 15-20 psi at idle but stopping and turning at higher g forces could produce almost 0 pressure. This needs to be avoided at all costs by modifying your driving habits. Some use 10W 50 to assure the motor has enough pressure to prevent metal to metal contact.

The low oil pressure, based on your description is a symptom of the idle dropping below normal. That happens in all cars so focus on the idle issue. Even if your pressure drops below the threshold, it is still circulating. Yes, it's not good for the motor but your heading is about oil pressure and really focus on the idle/running issue and your oil pressure should take care of itself. Don't change the oil pressure sensor, it appears to be working perfectly reporting sub nominal oil pressure when idle is sub nominal.

What ever happened with this? I have 100% exactly the same issue as described by OP. I can confirm the Idle RPM is not dropping lower than it did before

Im also running into this issue. I have a main oil pressure/ temp sensor plumbed into the main pressure plug and a mechanical sensor on bank 2 head as a reference. Starting everything is normal, but after heating up low oil pressure warning comes on and both sensors read 0. Any throttle input over 750-800RPM and the PSI goes back to normal limits building 10-20 PSI for ever 1k rpm. Just did an oil change with 5-40w, fresh Wix Racing filter. pressure tested radiator so no leaks in that aspect. Haven't pressure tested cylinders yet. Theres no unusual audible motor anomalies but hoping its not failing bearings. is there a way to turn idol up 100 rpm?

Sounds like a few issues together. Big guess here: Oil pump wear is allowing the pump to not provide enough pressure at low RPM (Possible the bypass path is slightly open). Possibly there is some ECU code that wants to maintain a minimum oil pressure, so as the oil gets hotter and idle pressure drops, the ECU tries to compensate by raising idle speed. Pump wear is such that this repeats till the "idle" is outside the window for idle, tripping other ECU conditions seen as errors. Maybe try a 10W60 oil and see how it works. (Warm the car gently) and see if it solves the issue. If it does certainly looks like a worn pump and/or an internal leak close to the pump (high pressure bypass)

Thank you for the response! I will look into that; I purchased this car with 133k miles with unknown history, which I'll admit was ambitious. I'm adding the upgraded 997 oil pressure relief valve this weekend (spring and piston). My intent is to make this a track car but before I add the UIDS, ultimate AOS with accusump and external oil cooler wanted to diagnose this further (hoping to squeeze 1 season out of the motor). I'm assuming next step should include removing the oil pump housing, inspect for cavitation and add the hex drive?

Before you spend lots of money on chasing this down - spend a small amount of money and replace the oil filter plastic housing - the parts that screws on. In the base of it is a pressure relief valve that has been known to fail with lots of miles on a car, and that can drop oil pressure. If that doesn't work - the use of a 10W-60 oil won't hurt anything - and might help. There is a secret behind the counter at AutoZone Castrol oil - made in Europe - called Castrol Edge TWS (Ten-W-Sixty). It was originally formulated for the S54 BMW M3 engine which had issues with rod bearings. The oil was supposed to stop that issue - it did to some extent - but not enough and BMW had a recall to replace all the bearings (this seems to be a common theme on BMWs). Audi then picked up on it - and the V10 in the R8 required its use. And BMW motorcycles made a HP (high-performance, no frills) model of their R1200 engine bike, and that engine spec'd the TWS oil. It was very good stuff when I was using it - and priced around Mobil -1 prices. The Autozone kids working there were always surprised when I told them to go look in the back for this "TWS" oil - and they had it in stock. Never out in the open, the public wasn't to know.. an under the counter (like Hustler used to be) sort of oil for the big boys..

First, I'm curious if these cars being discussed recently are 987.1 or 987.2 ? It makes a difference. I agree with Don that getting the stock filter and filter housing is a good first check. Someone mentioned racing filters, which always scares me. The oil pump is pretty robust. It's vanes and their clearances, which theoretically affects pumping performance, are going to last an order of magnitude longer than, say, bearings shells. Unfortunately, there are multiple "candidates" for gradual loss of oil pressure as these engines age. And yes, it might show up at idle first. In order of ease and cost- Replace the oil filter and canister with a Porsche OEM item. It is surprisingly cheap over the counter at a dealership. Rules out a couple of things. Go to a heavier weight oil. If running a 50W oil makes your light go away, that is probably a good fix. Replace the oil pump- I only suggest this because it is relatively accesible. Certainly doable versus changing out all the rod bearings or something. A 987.1 pump is surprisingly cheap at GetPorschesilverspringparts.com (~$350). The 987.2 pump is much more pricey. I seem to recall that Porsche started using a "demand" sensitive oil pump, in order to eek out small increases in fuel economy. Maybe others know the full story.