Lag on acceration

I have a supercharged 2003 Tacoma, and when you floor it, it does not accelerate right away, it will sit at the same speed for 2-5 seconds depending on speed then accelerate like normal. I took it to Toyota and they said it was because the engine was pre-firing so the computer was cutting the timing back, so they changed the spark plugs and told me to use premium fuel, but that only cut about a second off the time that it lags. I was wondering if there was any way to cut the pre-firing problem out completely.

 

Auto Tranny, and the spark plugs are the ones that Toyota recommended using, and we do not have much information on the supercharger, it was installed by the previous owner in california (Live in TX). The tires are 33's I think and I'll get the info on the gears.

 

Alright, and right when you floor it, the supercharger will pop all the way up too about 25-30 PSI then down to 8, which is where it should be, and it will do this probably two times then level out. All that in the 2-5 second lag it takes. That 2 seconds of lag is more like 1 second, and it takes that 1 second if you floor it at anywhere from 50-60 MPH, which is at about 4000 RPM in second gear, it will be 5 seconds if you floor it at around 35-40 MPH, which is about 2500 RPM.