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I also recently replaced the pedal assembly/potentiometer, and the results mirror yours. For the first few drives, the stumble was non-existent. Over the last couple of weeks, I will occasionally feel a very minor bump, but significantly lessened over the original, unmistakable, stumble.
P.S. - I'd like to see a Porsche tech remove the sensor clip without breaking it. Mine did not survive the process.
That is awesome. Add "new throttle pedal" to the major service every 4 years, lol. #justporschethings
Well, I'm about to embark on a definitive answer on this issue (in my case). I need to do my motor mounts anyways and have purchased the other 2 items just in case.
Possible causes from reading through this thread:
The Dynamic motor mounts causing a malfunction if they are bad or worn out
Bad throttle body - varnish or TB getting "stuck" or not moving freely
The GAS pedal, bad microswitch or potentiometer.
I will be installing these one by one over the weekend and seeing if it makes a difference as I go. Starting with the new gas pedal assembly. Then the TB if it still persists...then the motor mounts.
Well, I'm about to embark on a definitive answer on this issue (in my case). I need to do my motor mounts anyways and have purchased the other 2 items just in case.
Possible causes from reading through this thread:
The Dynamic motor mounts causing a malfunction if they are bad or worn out
Bad throttle body - varnish or TB getting "stuck" or not moving freely
The GAS pedal, bad microswitch or potentiometer.
I will be installing these one by one over the weekend and seeing if it makes a difference as I go. Starting with the new gas pedal assembly. Then the TB if it still persists...then the motor mounts.
This is perfect. Is your car displaying any warnings re: the mounts?
Are you going to reset the throttle adaptation after each? From reading the thread, it seems like resetting it fixes it for a while until the ECU re-learns this bad behavior.
I went and checked the "level sensor" module which I believe is the PADM unit....no faults in my little icarsoft tool.
Under DME module there were values for the item "misfires, 10 trips"....mostly in the teens. Guessing my mechanic had reset it recently. Not sure if normal?
I still don't understand how this only happens at load...if it was the throttle pedal or body, would it not be easily replicated by just revving it up?
Update #1 New pedal install was about 10 minutes. Pedal was $90 shipped. same part number as above. Just use a straight pick to slide under the connector clip to pop it off from the pedal.
Happy to report that 90%+ of the stumble went away...might be all of it...? Last night the drive was so much smoother. IDK if I was being "extra sensitive" looking for a stumble or it just variations in the road ( bumps etc.)
The 991 was already warm from an earlier drive. I will drive it today and see how it acts under a cold start and in regular and manual modes. But very promising. Side note: My gas pedal needed to be swapped anyways, it seemed to have a "dead spot" when first putting pressure on it to drive from a stop, now that I have a new one I know mine was junk. So if you have a little play in yours, change it out. Feels solid now.
Next up is the throttle body tomorrow...then the PADM engine mounts.
Last edited by GermanCarFan1; 06-09-2023 at 01:34 PM.
Update #1 New pedal install was about 10 minutes. Pedal was $90 shipped. same part number as above. Just use a straight pick to slide under the connector clip to pop it off from the pedal.
Happy to report that 90%+ of the stumble went away...might be al of it...? Last night the drive was so much smoother. IDK if I was being "extra sensitive" looking for a stumble or it just variations in the road ( bumps etc.)
The 991 was already warm from an earlier drive. I will drive it today and see how it acts under a cold start and in regular and manual modes. But very promising. Side note: My gas pedal needed to be swapped anyways, it seemed to have a "dead spot" when first putting pressure on it to drive from a stop, now that I have a new one I know mine was junk. So if you have a little play in yours, change it out. Feels solid now.
Next up is the throttle body tomorrow...then the PADM engine mounts.
this is great news! you didn't reset anything right? just a simple swap?
Originally Posted by koala
We're going to have to start hoarding throttle pedals out of wrecked 981/991's before everyone else catches on that this might be the real fix, lol.
how do we know the used ones we are buying are good?
debating whether to spend the extra to get a new one.
Originally Posted by Sajan
ah thank you. i missed that.
I wonder what the other different part numbers mean in the catalog. maybe manual vs. pdk, and regular vs. sport..?
970-423-019-01 - $312 - manual
991-423-020-01 - $596 - manual, sport
Took the 991 out for a drive from cold start and drove around town and then for a spirited drive. Happy to report that it's "almost" non existent. I've got the rear all torn apart doing the TB and Engine mounts.
My throttle body does have some play in the flap, about 1-2mm...the new one is solid and doesn't give.
I think this might be there remedy for the remaining 5-10% of the issue for me.
Mine is a manual. Not sure what the distinction is for the 'sport' version but the manual (non-sport) 970 part number works and I can't notice any difference in any drive mode. I do drive in sport+ 99% of the time, tho.
I suppose there is a percentage chance that a used one could be problematic but I figured a) I have a gambling addiction and it's too tempting to save a few hundred bucks and b) hopefully getting the part out of a newer model year car with fewer miles should lower the risk a bit
05-28-2023, 10:57 PM
