I have a 05 5.3 motor w/ th400 and DBC throttle body. It has a mild cam in it but I have no idea what the specs are. 28lb injectors on returnless fuel system. I am using the corvette regulator. I have tuned the VE table and Maf and both seem to be in line with each other. I have adjusted my IAC counts. I have also moved the IAC Steps vs Effective area 6 places to the right. I feel like I have a decent running motor except for this one issue. From a cold start I will log Dynamic and Desired numbers using Russ K method and let all the cells populate. Turn off LTFT and zero out adaptive idle. After the engine is warm I insert those numbers into the correct place, upload the tune, and start the engine back up. Now the Dynamic and Desired numbers are completely different and much lower. Engine acts like it has way to much air and revs on start up, acts like cruise control. If I go back to the tune and upload the "new" desired lower airflow number the engine acts much more stable and normal. LTIT and STIT are more in line. I have shut off the truck at different times when warming up to see when the airflow numbers would change and from what I can tell the lowest I have been able to see the switch is around 130F. There is also this problem when it's cold and warming up, if I press the throttle it stumbles and my wideband spikes super lean to around 20. Doesn't matter if its cold or warm, it still spikes lean and stumbles. It's like I have to let the engine warm completely up, shut the engine off, and then turn it back on and everything works as it should. No lean spike when I press the gas, engine seems to operate fine.
Any ideas on where this problem could be coming from?
Could the Map sensor have anything to do with this? I'm showing 92 kPa with ignition on, engine off, when i've read it should be between 95-100 kPa. Also with the engine idling from a cold start I am showing 42 kPa. When I shut the truck off and restart it now it idles at 44 kPa.
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