Bucking/sluggish performance

[Robvan80]

My 2002 TB is sluggish and bucking consitantly between 65 and 70mph at low rpms...any advice
Already changed spark plugs and Coil packs

 

[Tdub]

How is the transmission fluid, and are there any codes?

 

[Robvan80]

No codes, fluid level is normal

 

[Tdub]

Can you watch misfire counters with a scantool or something like torque pro?

 

[Mooseman]

As well as fuel trims and MAP data would be useful.

Could also be the torque converter clutch slipping. When it's doing it, tap the brake to disengage it and see if it goes away.