[s-cars] S4 bucking under WOT - what else?

[chris chambers]

Ivan,

If it "bucks" and feels like the fuel pump shut off then it 
could be a bad maf or dirty contacts on the MAF or its cable. When the
MAF causes this problem it's because the ECU believes the car is
overboosting and cuts off the fuel pump.

I see you "cleaned" the MAF, what did you do? I had the same problem
and fixed it by using electrical cleaner to spray and scrub the
contacts on the MAF and its cable clean.

If it accelerates but accelertes hard and is rough while doing so then
I would look at the Coils or POS. Re-check each of the coils with a
manual spark plug tester increasing the gap until you either get a coil
to test bad or all of them to test bad (meaning they are all equally 
good).

HTH
Chris

PS I purchased a cheap manual spark plug tester at Autozone for ~$6

AUDI - Accelerates Under Demonic Influence.

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