[s-cars] Bucking Bronco when accelerating...

[keithbedard at verizon.net]

A couple of weeks ago, my S6 (~152K) started doing this “bucking” thing, whereby whenever I accelerate from a stop, accelerate medium when already moving, or accelerate hard at high speeds, the car bucks like a rodeo, but eventually smoothes out.  I have gone through POS and coils, and these have been ruled out.  Couple nights ago, I replaced air filter and fuel filter, with no change.  Car has Samco hoses, and last weekend I did air leak test with air hose, and there are no apparent leaks.  It is not throwing any codes.  Car does not seem to throw smoke.  Idle is a little inconsistent, and has rough running short moments.  Granted, I haven’t looked at my spark plugs in a couple years, I will do that soon, but I doubt that will be the issue.  

Any BDTs are very appreciated.  

Thank you,
Keith Bedard
Templeton, MA