Even if boundary layers are just a few millimeters, yours is still like an inch away from where the air is going That was my point. Its not actually in an air stream at all. But nobody really taps into the runner for IAT... My comment about changing the bias and filter values were assuming the IAT sensor was not in the intake.

 

Just to update this thread, I am still having problems with the truck leaning out the longer it runs. I messed with it today and have read a little bit on the EFI Live forums the past few days, and it looks like the heat soak is my issue. When I start the truck and drive it, everything is pretty much fine until I shut it off for any extended period of time. Once the intake is hot it is that way for hours. The other night it was 71 degrees out, I had the truck shut off for 3 hours and it was still reading 99 degrees. What I am understanding is GM blended the IAT with the ECT in the tune. So when my IAT is reading 140, and it is 70 out, it is really out of wack. So it believes it is 140 outside and my engine is warmer than that making the air entering the cylinder appear to be warmer than it actually is making the lean condition. I eliminated the ECT blend all together and got a pretty good improvement. It was still off, but much closer. That is as close as I can get it by just tuning. I imagine I could get a plastic or phenolic pipe adapter to keep the sensor off the intake, but it looks like I will be moving it to directly after the intercooler.

 

Your IAT sensor itself is more than likely getting heat soaked like you've mentioned. There aren't any phenolic bushings that I know of but there are PTFE. There good for 260F and 200psi
Pipe fittings Reducing bushing Chemfluor PTFE 1 2 NPT M x 1 8 NPT F 1 1 16 x 7 8 x 5 16 - Reducing bushings NPTM x NPTF from Cole-Parmer Canada

There's also Nylon but I'm not sure of it's specs
THB32 3/8 Male NPT x Female NPT Reducing Bushing | Plastic Fittings & Adapters | Hose in a Hurry

Just tap your hole a but larger and install.

 

Thanks for the links. I actually moved it today to the outlet of the intercooler. It seems to have cleared up the lean condition I was experiencing. Im glad I moved it.

 

I'd think your sensor is heat soaked to the same temp as the manifold, It wouldn't fluctuate much because the manifold and sensor is hotter than the air passing through. Especially with the location of your sensor there is little airflow across it so it wouldn't fluctuate much. It will definitely keep you on the safe side since it will be reading a higher temp than what actually is being ingested.

 

This is dangerous not safe. It is calculating that the temperature is higher suggesting the air is less dense causing a lean condition.

 

^ Lol, I was thinking the same. Bad things can come from reading too hot or too cold...better just make sure its correct. lol

 

I didn't consider the fuel side of it, I was thinking timing.