So until i have another engine built and ready to go, I'll probably hit the tracks a few times by summer time with my current engine and its setup. It's a 06 GT with 120k miles with a vortech centri blower and few other mods all previously done by last owner. It currently runs fine and pulls strong, but lately its got a problem of surging a bit after i let off the gas pedal. It's annoying enough that i hope there's a fix before i take it to the track. - Let's say im cruising along about 40mph and let off the gas, for the next 2-3 secs it will surge a bit as if i'm goosing the pedal on and off very lightly, and will do it about 2-3 times. I'd say it raises the rpm no more than 50rpm when it happens, but it was just enough to feel like as if you dipped into the gas pedal again. - There are no codes and no check engine lights. The engine doesnt make any unusual noises. It doesnt smoke or noticeably use any oil either ( I havent driven it long enough since i own it to see a noticeable amount of oil consumption). - I have installed a new set of spark plugs with 0.032in gap, cleaned the air filter, and cleaned the MAF sensor with MAF sensor cleaner. - Ive brought my car back to the tuner that previously did the tune to let him check the car out. He works on mustangs only and his shop is always packed. He looked at the tune, took the car for a long test drive with datalogging, and said he found nothing in the datalog or the tune that could contribute to what i described. He said without investigating further, at this point he's most suspicious of my BBK 62mm tb. He suggests his customers to just stick with stock tb unless they have huge hp goals to reach. - I've read up on people having bad experiences with BBK tb. But before i randomly just drop money onto another tb, is there any other things i could check to confirm it is my tb acting up? I wonder if it needs cleaning, but it seems like it takes a little bit of work to undo the charge cooler that bolts up to the tb to get access. it may be what i have to look at next time when i get to work on the car. I do not have the luxury of having the time or space to work on the car anytime i want. It'usually one afternoon a week so i got to plan ahead what i'm going to do and get the parts ahead of time, and hopefully i have all the right parts on hand.