At times in 4th gear @ around 5000rpm in WOT the car would hit fuelcut or what appeared to be. mods at most are K&N filter, tb mod and hollow cat.

I was told that in fact the car was detonating. So i was advised to put check valves in the vac. line that goes into the pressure sensor, and the hesitation is gone, essentually no more fuel cut. Are there any down falls in using this method? could this be an alternative to purchasing a FCD?

thanks.