Idle drop while braking,backing out of driveway

[1994rcsbLS]

OK, first:
Swapped 94 short bed, 6.0 LQ4 with work. Holley terminator X( she's tuned )
Cam: TSP magicstick3 cam 238/242, .600'/.600', 112 LSA, 110 ICL ( and all valve train upgrades required for it )
Turbo 400 with a 2800 stall converter ( this is what i was told was in the trans, yes im aware of TSP says for 3800+ stall )

Issue: During braking( usually coming to a stop light/sign/ traffic ) the trucks idle dips and almost wants to stall. my normal idle is 9xx-1050, while braking and coming to the stop it drops to about roughly around 700rpm. once stopped the idle levels out and is fine.
Drives fine, normal idle fine.
I recently did plugs. wires, pulled injectors and cleaned them well. I checked for vacuum leaks thoroughly, I did basic brake booster checks and haven't noticed any differences during testing that would make me believe its bad( and looks like was replaced ) what i did notice was a soft spot on the hose closest to my intake, but no tears, cracks.

I'll be testing vacuum within the day or so, but i'm running out of ideas....

 

[Scooterwrench]

On that Terminator X can you dial in fast idle decay? When and how much?
You may want to have it come on at a little higher speed and/or decay at a slower rate so it eases it down to idle. Also how many steps is it opening the IAC when you crack the throttle. That big cam will need more bypass air(more steps) when your off idle. Don't do all three at once. First try adding air then speed,then decay.

 

[1994rcsbLS]

On that Terminator X can you dial in fast idle decay? When and how much?
You may want to have it come on at a little higher speed and/or decay at a slower rate so it eases it down to idle. Also how many steps is it opening the IAC when you crack the throttle. That big cam will need more bypass air(more steps) when your off idle. Don't do all three at once. First try adding air then speed,then decay.

I’ll have to plug into it and check, I’m not overly familiar with the system if I’m being honest. So I’ll need to get back to yah.

 

[Scooterwrench]

I recommend getting familiar or you'll be paying someone else a lot of money to do it for you.
If that's your truck in your avatar pic,that's pretty sharp.

 

[1994rcsbLS]

I recommend getting familiar or you'll be paying someone else a lot of money to do it for you.
If that's your truck in your avatar pic,that's pretty sharp.

Ooo yeah. Got that right. Lol
And yes that’s her alright. “My other woman “ lol

 

[Erik the Awful]

I recently did plugs. wires, pulled injectors and cleaned them well. I checked for vacuum leaks thoroughly, I did basic brake booster checks and haven't noticed any differences during testing that would make me believe its bad( and looks like was replaced ) what i did notice was a soft spot on the hose closest to my intake, but no tears, cracks.

Did you vise-grip the brake booster hose closed and try pushing the brakes to see if the idle dip goes away when pressing the brake pedal?
Note: Do this in your driveway, not on the road!

 

[1994rcsbLS]

Did you vise-grip the brake booster hose closed and try pushing the brakes to see if the idle dip goes away when pressing the brake pedal?
Note: Do this in your driveway, not on the road!

That’s on my agenda when I wake up. 12 hr shifts suck. Plus gives the neighborhood some time to wake up haha now assuming the idle dip doesn’t happen while clamped off I could probably assume it is In fact booster /vacuum related ?

 

[boy&hisdogs]

That’s on my agenda when I wake up. 12 hr shifts suck. Plus gives the neighborhood some time to wake up haha now assuming the idle dip doesn’t happen while clamped off I could probably assume it is In fact booster /vacuum related ?

Yeah that's something I have heard before as well. A leaky vac booster can cause all kinds of issues and pinching off the hose isolates it.

 

[HotWheelsBurban]

Ooo yeah. Got that right. Lol
And yes that’s her alright. “My other woman “ lol

An old family friend in Austin had a radical custom '50 Chevy pickup he built, that was the ISCA champion in 1967 or 68. His wife said he spent enough time on the truck, that he was more into it than her(they did have 4 sons together so that hadn't always been the case!). So the truck got named "My True Love"....

 

[1994rcsbLS]

On that Terminator X can you dial in fast idle decay? When and how much?
You may want to have it come on at a little higher speed and/or decay at a slower rate so it eases it down to idle. Also how many steps is it opening the IAC when you crack the throttle. That big cam will need more bypass air(more steps) when your off idle. Don't do all three at once. First try adding air then speed,then decay.

Okay, so I hooked up my laptop to it. Let her warm up and logged a trip. While braking coming to a light. Pedal felt fine before stall. Went to stall. Pedal got hard, saved it. Pedal normal. Got to stop.
Here’s my table for idle :

You must be registered for see images attach