Intermittent Engine Power Loss

[Hobbes]

I'm looking for some help to diagnose an intermittent engine power loss problem I've been having over the pass several months. I have a 2000 996 C2 with ~180K miles.

 

Problem:  The 996 runs great typically on short drives, <75 miles.  With prolonged driving the 996 will suddenly lose power with the engine bogging down as if going into limp mode for about 5 seconds then full/normal power is restored.  After the first occurrence of this event during the drive, the event will happen again about 60-90 seconds later, then lose power again for 5 seconds.  As I continue to drive the 966, the frequency of the cycle increases going from 60-90 seconds to every 25-30 seconds; however, the bogging period last only 3-5 seconds per event cycle regardless of the frequency of the event.  This cycle of events only after extended periods of driving.  There is no CEL or fault codes from Durametric or OBDII scan tools.

 

I've replaced the fuel pump and fuel filter.  I cleaned the ground points and positive terminals.  Coils and spark plugs replaced.  I cleaned the throttle body and MAF.  I replaced the throttle body (TB)  with a spare to include the throttle position sensor on the TB. 

 

Given all of this, I am leaning towards the E-gas sensor just off the accelerator pedal (PN: 99660611500 / 99660611502) given the age and miles on the 996, my inclination is that this sensor is going bad, but I'm not entirely convinced since the problem only presents itself when a certain amount of driving occurs.  If it were this sensor, I would think I would experience the problem shortly after startup and driving, but I may be wrong with this assumption.

 

The short video shows the symptoms of the problem while driving.

 

Thanks,

Ken

 

 

IMG_4311.mov

[judgejon]

I would have to think e-gas as you have seemed to have done everything else.

Try running a durametric check for codes, and you could also clear the airbag light.

good luck.  I'm guessing the real pros on the forum will wade in on this for you.

[Hobbes]

Update: Problem resolved.

 

I replaced the accelerator position sensor under the dash.  I've been able to drive without power loss; I even noticed a little quicker acceleration.

[Loren]