I have had this issue for about a week now ever since I changed my IFR table via a spreadsheet Tommygloves and I have been working on to calibrate my DIC mpg with my 42lb injectors. I also reset the MAF to a stock LS6 at the time to start MAF tuning fresh with the warmer weather. (have N* and LS6 maf). This could have been a coincidence though. At idle my car sits at 16.41 LTFT and when I let off the gas cruising. At other throttle positions it is normal for a untuned MAF table, and im not concerned. This only happens when the car is warmed up. When its cold the idle trims seem kinda normal. Wideband also pegs lean when I let off the gas if im going fast enough (I was told this was normal). Thinking this could be a vacuum leak I searched last night for one. I found a big rip the rubber T under the snout. Drove around trying to find a new one at 8:00 at night but failed, I was later told this is a dealer only part. I bought a plastic T and some fuel hose and made a new vacuum T and installed. After resetting the fuel trims and driving around for a bit the LTFT's went back to 16.41.
I don't really think this is a tuning issue but rather a vacuum leak somewhere, that I cant find. I read this post on clubgp and think I may also have developed a leak, because I am running these same ZZP garlock supercharger gaskets.
http://www.clubgp.com/newforum/tm.asp?m=4809538&p=1&tmode=1&smode=1
I don't really think this is a tuning issue but rather a vacuum leak somewhere, that I cant find. I read this post on clubgp and think I may also have developed a leak, because I am running these same ZZP garlock supercharger gaskets.
http://www.clubgp.com/newforum/tm.asp?m=4809538&p=1&tmode=1&smode=1