Car hesitates at 5500rpm??

Hey ppl....ive has a slight problem for just over a week now, and i cant seem to find the problem. Tried checking the net, but havnt found the answer...

I took my car for a spin the other day, and when i accelerated hard in second gear, as the revs approached 5500rpm, the engine hesitated, felt like the car had no power, and again the same problem in the other gears.... but it only happens under hard accleration...if i speed up slowly no problems, kinda strange....

i had a diagnostics done from a mate...(he has one of those plug in units) it came up with 1.o2 sensor
2. air mass meter
3. igniton coil 1

could any one of those be causing this problem im having, any help would be really appreciated, thanks!

let me know if you find an answer to this as mine does the exact same thing.

Also the car doesnt seem to have as much power as before

Hi is there anyone that can answer this for us???????

mine does it around 2-3k

mine was doing it round 1.5K-2.5K rpm. Also did a diog on the car. it came up with o2 sensor, mass air flow meter and mechanical jamming on vanos. replaced the vanos and re-seated the o2 sensor. all is fine now

something else that cant hurt is to try this stuff http://www.bgprod.com/products/fuelair.html get the 44k in the can put it in the tank with about 1/8 of gas left and run the car down to almost nothing then top the tank off with premium gas. We have been using this for years and it does work. This stuff usually cost @20 a can.