RTT problem solved

Using SD OS i was having problems with fueling changes having no effect on AFR. It would effect it briefly then correct itself. I assumed i was in SD mode by loading SD OS.
I went to my MAF table and zeroed it out. Truck would start but run poorly. So i went to DTC and by default with SD OS P0103 code was set (No error to report) i set it to (MIL first error)like i normally do to force MAFLess. RTT works great now. Just a simple not in SD mode was all it was. This may already been covered if so I apologize for duplicate post.
2002 silverado P01 ecu

Having the code P0103 is pretty important for speed density tuning. Nothing wrong with posting what you have found, it's threads like this that could help someone in the future if they are having issues that could be as simple as this.

This post helped me.
I've used RTT to tune the VE very effectively on several engines. Then I decided to removed my MAF entirely to see what difference it would make. I then turned the MAF DTC's off by setting them to not report an error, and then lost RTT control of the VE completely. I came on here looking for answers and found this thread, and now I remember having the same problem years ago when I started using RTT. I just goes to show that there's so much to keep track of that it's easy to make simple mistakes that take you backwards.

One thing I did learn from this experience is that the tune became about a half point richer without the MAF hooked up. That was actually a good thing because it seems to be making more power (per the SOTP dyno) with more fuel. I hope to confirm this at the track tomorrow.