I've recently noticed while driving my 01 a4 1.8t feels like its chugging a little when I've got my foot on the gas. it almost seems like the gas isn't being provided consistently. it happens every once in a while and isn't always consistent. I first thought it was because it was getting colder and was noticing after I would let the car warm up after for about 10-15 minuets so i started letting it warm up for 20-40 minutes and I wasn't noticing it anymore but today on my way to work it started again. i know my explanation may not sound very well but if anyone has any ideas that would be great.

bought the car in Nov with 144k
seafoam 100 miles before an oil change with gsx synthetic and K&N oil filter
seafoam in the gas
seafoam in the intake manifold but never saw any black smoke
Shell premium gas