full throttle miss - B5 A4 1.8t

[Lee Levitt]

Patient is an '01 B5 A4 1.8t with 130K, recent coilpacks, APR 
chip. Nothing has been changed on the car in the recent past.

On heavy throttle, it feels like I'm dropping a cylinder at 2800 
RPM. Nothing lower, and nothing at part throttle.

When I've lost coilpacks, the power loss is a lot more severe. 
This is more moderate, feels a bit like hitting the rev limiter.

Any thoughts on what this might be? Bad spark plug? Fuel filter?

If it matters, the car is silver.

Thanks!

Lee