I purchased a 2005 S type 4.2 at the auction and they announced a transmission issue due to a massive surge. I drove this for about 100 with the surge and no check engine light. All the search results for surge came up with a transmission TSB.


It turns out that the issue was the Intake Air Duct coming off of the throttle body causing air to bypass the MAF.

 

Good find!

Oooh, and it has to be a cheap fix compared to what it MIGHT have been!!

edit: just noticed the title.... some of us EXPECT a surge at WOT

 

Was this caused by a broken or loose clamp?

 

loose clamp, most likely from another dealer that pulled it off in order to get the car at a low price.