strange behavior, can't replicate
Thread Starter
Instructor
Joined: Dec 2011
Posts: 119
Likes: 0
From: NoVA
strange behavior, can't replicate
Yesterday during a short trip back to my house, the 964 was wanting to stumble under load. 'Stumble' isn't exactly right...it was more like a sudden departure of power. It never stopped running, and it would recover if I eased off the gas. It was as if the air flow meter hit a dead spot at a certain point.
While diagnosing a similar problem 18 months ago, I rebuilt the AFM, cleaned the ISV, replaced the DME, and ended up fixing it with an oxygen sensor. That problem was more random, however. This episode was distinctly happening at a certain load point, or a certain throttle position (couldn't tell which).
Only thing unusual when I got back home, was I had my AC switched on unknowingly. Could a compressor clutch problem or wiring issue be causing this? I drove the car around today, and it was fine. Other than that, the weather was pretty chilly yesterday...could the temp have been throwing something out of whack with the AC?
While diagnosing a similar problem 18 months ago, I rebuilt the AFM, cleaned the ISV, replaced the DME, and ended up fixing it with an oxygen sensor. That problem was more random, however. This episode was distinctly happening at a certain load point, or a certain throttle position (couldn't tell which).
Only thing unusual when I got back home, was I had my AC switched on unknowingly. Could a compressor clutch problem or wiring issue be causing this? I drove the car around today, and it was fine. Other than that, the weather was pretty chilly yesterday...could the temp have been throwing something out of whack with the AC?
Rennlist Member
Joined: May 2007
Posts: 2,295
Likes: 37
From: Portland, Oregon
Mr Spacely,
I'd be interested in what you find... At one point or another many of us have experienced something similar... cruise conditions, sometimes it feels like the engine just isn't getting what it needs - a light stumble, but then if you increase/decrease throttle it goes away...
I would guess it's an electrical worn or dead spot in the AFM, but that's just a guess.
I'd be interested in what you find... At one point or another many of us have experienced something similar... cruise conditions, sometimes it feels like the engine just isn't getting what it needs - a light stumble, but then if you increase/decrease throttle it goes away...
I would guess it's an electrical worn or dead spot in the AFM, but that's just a guess.
Nordschleife Master
Joined: Jul 2007
Posts: 5,613
Likes: 52
From: DFW, TX
Mine started like that. Kept getting worse to the point the car was not driveable and would sometimes stall in stop/go traffic.
Hopefully I'll put it back on the road this month w/ a bunch of new parts and it'll be fixed.
Hopefully I'll put it back on the road this month w/ a bunch of new parts and it'll be fixed.
