Acceleration stumble at highway speed Help!
I am hoping that someone on here can point me in the right direction for the issue that I seem to be having. 2004 zhp auto with 105,000. About 2 weeks ago I started to notice a high speed acceleration stumble when I am trying to accelerate from a cruising speed of around 70. The car has near perfect smooth power throughout the whole range up till this point but if I ask a little more of it there is a noticeable stumble like it is being starved for fuel or has a bad misfire. It will eventually get to where I am asking it to go but not without a stumbling jerking feeling throughout the whole car. Verified by cruising at about 70 then opening up the throttle to accelerate up to 90, it will get there but it doesn’t seem to like it. It is fine around town and will only give me this problem on the highway. Since this probably has more to do with cruising rpm than speed, at these speeds in 5th rpm is around the 3,000 range or a little over. My wife says that I should just slow down but there is obviously a bigger issue here.
Maintenance in the last 20,000 miles includes: fuel pump, fuel filter, spark plugs, silicone intake boot, rebuilt DISA with GAS kit, rebuilt VANOS with Beisan Systems seals. Valve cover gasket, and probably a few other things I am forgetting. I am thinking possible causes could be O2 Sensor, camshaft position sensor, VANOS solenoid, coil pack, vacuum leak? I have no codes and no issues in the lower power range.
Any more solid ideas would be greatly appreciated?
2004 330i zhp