Car is a 2004 audi a4 1.8t sport w/ manual transmission

Between 3k-4k RPMs and ONLY in 3rd or 4th gear the car SOMETIMES "hesitates" (like its going to stall out) then keeps on accelerating. Any ideas here? It tends to do this more so when you accelerate faster

I do need an oil change badly, and there is a coolant leak.

Thanks

 

I'm not an expert or anything, but it probably happens in every gear, you just don't know notice it because it's not to the same extent that it happens in 3rd or 4th. If it happened ONLY in 3rd or 4th, then there is a problem with the drive-train. In my opinion, it might be a boost/vacuum leak, or a faulty sensor.