I've got low idle vacuum and stumble on throttle tip in along with knock under load. I swear it's a vacuum leak but I've done everything to try to track it down and can't find one. (pressurize the intake/engine and use smoke and spray down the whole bay with windex to look for bubbles) Is there a way to "test" the MAF just to rule that out?

 

I tuned a ws-6 that had the exact same issues. It ended up being the MAF. If you have tuning software you can fail the MAF and run in SD. If it runs better then you've found your problem.

 

I have efilive, but I had slowhawk tune my truck. I got efilive after the fact so I could try to learn myself on a truck that was already tuned. I'll go figure out how to turn it off and see what that does.

 

Since you have a Radix, your IAT is already relocated out of the MAF. You can just unplug the MAF, and it will switch to the VE table and run in speed density. No tuning software needed.

 

x2 best way to check if something is not working is just unplug it and see what (if anything) changes.

 

What you are describing is exactly what my 99 Sierra was doing. The easiest way I checked the MAF was just swapped it with my dad's truck. However, it wasn't the MAF, ended up being the MAP sensor in the back of the intake area that fixed it....I thought for sure it was a bad MAF.

 

when going from MAF to Speed density what do you do with the MAF harness

 

Find a spot to tuck it away.

 

Permanently?

 

Or temporarily. Thats why he said tuck it away out of sight, not cut if off.