Simple question for you tuning experts. Should the MAP readings move around quite a bit during normal driving? I'm seeing 30kPa up to 70kPa with with some easy driving. It just seems very noisy even when moving along at steady speed. I haven't done much logging in years and I'm troubleshooting a stalling issue when my truck is shifted from park to drive or reverse.
Thanks

 

Yes, that's completely normal. The MAP sensor is very sensitive and will constantly react to throttle changes, even small ones, and engine load. Your readings are exactly what you'd expect during easy driving. For your stalling issue, focus on your Idle Air Control (IAC) valve or vacuum leaks.

 

Thanks. It's a drive-by-wire TB on an '05 5.3L motor so there is no IAC valve. I believe this style just adjusts the main TB blade for correct idle airflow. I cleaned the MAF a second time (my son did it the first time) and it seemed to idle a little higher last night while in gear. This is making me think I might have a MAF issue. I'll drive it again tonight to see if its better. It didn't stall during a short test drive last night either.

 

That's good progress. A dirty MAF can definitely cause those exact idle and stalling issues on a drive-by-wire truck. Since cleaning it helped, you're on the right track. Drive it and see if the problem is solved. If it comes back, the MAF sensor itself might be going bad.