Rincon Stalling

Hey guys, I've been having problems with my '07 Rincon stalling on my in the mud. It doesn't happen anywhere else. If I get into a situation where I need to back up, It will sometimes stall when I let off the gas. Its been happening for a while now, but I just work around it since I'm not always riding in the thick stuff. I will use an example from 2 weeks ago, i was trying to crawl out of a mud hole that was just over my floor boards when the quad dies after I let off the throttle, right when I want to put it in revo. I have no problems any other time, climbing hills, doing wheelies, stoping for a second then putting up steep inclines. I am wondering if there is something wrong with my optimizer, I have it set to what HMF says to, and it runs fine. I messed with the settings a few times because I run the quiet core in the exhaust, but it still runs the best on the 4-5-4 setting. Don't know what to do about it. Can Anyone help?