I took my 00' V6 Manual to the dealer today to have it checked out. My problem is like 00_ls_slow_5spd's Loss of power during acceleration in 4th gear. I have the intake and exhaust and I have noticed a slower acceleraction in 4th gear, from 60-80. it kinda builds up then takes off. I had them check the fuel system and they said it was fine. They ran like four tests and my Ls passed all of them, they road tested it and said it was because of my 20's that it takes more time to rev up and go then if I had 17's...I call BS because this has only been within the last few weeks...I have had 20's for over a year, and I even have lighter foose 20's now, then my original 20's. I checked all my connections in my intake system and everything is tight. I had added a peice of ducting from the lower grille to the intake area, to bring cooler air in and so I took that off and it seemed to get a bit worse. I am totally lost on what this could be. Any ideas will help, I checked the MAF too to see if it was dirty and it looked fine. Sorry for the long post, but I wanted to give as much info as possible.