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Matt
Matt, Engineer
Category: Car
Satisfied Customers: 20801
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
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My 2002 Porsche 996 Carrera 2 has 45000 miles. Yesterday while

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My 2002 Porsche 996 Carrera 2 has 45000 miles. Yesterday while pulling onto an uphill climb from a side street the car lost power. I clutched in and tried to rev the engine, but it acted like it was low on fuel. I let it idle thinking it would die, but it loped between idle speed and about 500 RPM above idle speed. I rolled backwards into a K turn and coasted down the hill, all the while the car idled but wouldn't rev like normal. After about a minute the engine smoothed out, but the rev response was sluggish compared to normal. I was able to drive up the hill and home, but the engine feels like it has less torque and power. There are no dashboard indications of trouble and no trouble codes are found with Autotap on the OBDII port. It feels like the ignition timing or valve timing systems stopped performing optimally and the ECU dropped back to a compromised running mode. Could it be a failed engine sensor, or a failed hydraulic cam timing actuator? What should I check next?
Hi

I woudl check the intake system for air leaks after the airlfow meter, as any air pulled in post meter is not seen by the ECU and so the engine runs lean.

The best way to find air leaks is have the engine running and warm and spray lighter / butane gas around each joint if the engine rev's up you've found your leak.

Potentially the airflow meter may have failed and the car is running off other sensors, I woud lexpect this to show up on the OBDII port though.
It may be worth unplugging the meter to see if this makes any difference as they can sometimes fail in such a way that isn't recognised by the ECU.
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Customer: replied 7 years ago.

I checked for leaks with propane and by inspection. There weren't any leaks (that I could detect). I ran he car with the mass air sensor disconnected. The engine seemed to run the same, but the car computer showed the Porsche Stability Management and ABS systems failed, and recommended I drive to a repair shop. I drove a good distance with the mass air sensor plugged in. On the flat at about 80 I normally get 26 to 28 mpg. I got slightly higher, 30mpg, but about half the miles were at 55 in traffic on aXXXXX It seems like some of the low end torque came back. The same hill the car previously stalled on it pulled up 35mph in 4th gear. It still seems sluggish compared to a few days ago.

Hi

Did you try driving the car with the airlfow meter disconnected?
Customer: replied 7 years ago.
I ran the car with the mass air sensor disconnected. The engine seemed to run the same, but the car computer showed the Porsche Stability Management and ABS systems failed, and recommended I drive to a repair shop. I drove a good distance with the mass air sensor plugged in. On the flat at about 80 I normally get 26 to 28 mpg. I got slightly higher, 30mpg, but about half the miles were at 55 in traffic on aXXXXX It seems like some of the low end torque came back. The same hill the car previously stalled on it pulled up 35mph in 4th gear. It still seems sluggish compared to a few days ago.
OK

If the car drives the same with or without the meter connected then theres a strong case to say the meter has failed.

Ideally between driving it with and wthout the meter connected you can remove the positive battery cable for 10 mins to reset the ECU so you're comparing like with like.
As with most modern cars it will sort its self out to cope without the faulty sensor and 'learn' / remap itself as required, removing the battery cable clears what the ECU has learned.

As the meter is likely to be expensive it may be worth confirming this with a diagnostic check at a Porsche specialist.

Customer: replied 7 years ago.

I took the car to the local Porsche service center. They connected it to their OBDII computer. It showed a failure P1325 Inlet camshaft bank 2, intermittent, not present.

 

They think the problem cleared itself. It may be foreign matter in the oil fouled the hydraulic line to the cam timing adjust vane actuator.

 

Your advice has all been helpful. I'm new to JustAnswer. Do I owe you more than the original $15?

 

Thanks for your advice.

 

Customer

Hello Rick

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