[s-cars] S4 hesitates , stumbles at elevation

[qshipq at aol.com]

 I don't think it's coils at all!? You failed to mention if this was a stock ecu or tweeked, boost levels, injectors, etc..? Many (if not all?) tweeked ecu's ignore the altitude compensation in the reprogramming.? It's quite possible that the long term fuel trim values didn't compensate fully, the charge air temp sensor was dialing back timing, and/or the car was just running hotter thru the hills.? Is the belly pan on the car?? 

Ideally, there should be no difference in performance as you climb into the mountains.? That's not *always* the case.? But I sure wouldn't start at failing coils, not enough information for that diagnostic IMO.

My .02

Scott J


 


 

-----Original Message-----
From: George Verbryck <georgeverbryck at yahoo.com>
To: s-car-list at audifans.com
Sent: Wed, Sep 30, 2009 4:03 pm
Subject: Re: [s-cars] S4 hesitates , stumbles at elevation










Well I have gotten several replies for coil failure as the suspect. This 
unfortunate as the coils are the newer 2.0t coils for 06+ cars.The new style 
coils are beefier and bigger but I guess have not fully addressed the problem 
yet. I was trying them out in hopes I would not have to replace the whole coil 
system again . The plugs were changed at the same time with the NGK Iridium. I 
bet they do not have 5000 miles on them . I have the Apikol coil harness.? Again 
on flat land? I have no symptoms, I guess the extra umphh of passing uphill 
exposes coil failure quicker. In the meantime I can just wait for it to get 
worse, great. On the bright side it was still a great drive and I do not live in 
the mountains so I will not have to be dissapointed everyday. Regards, George



      
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