Starting to try and figure out how to get flex fuel working using a 512 KB PCM. I have found the couple of L59 OS's over on the Tune Depot, but noticed that those are for a DBW setup. Internet reading says that you could have an L59 in either the truck or SUV. The Tahoe/Yukons were some of the 1st vehicles that got the DBW. I am hoping that maybe a Silverado L59 would still of had the DBC. Does anyone have a copy of an 512 kB L59 OS which still used the DBC? The couple of files which people have shared on this forum have also been DBW. I would prefer to try and keep a DBC setup instead of the DBW.