2015 Mustang GT fuel trims changing at full throttle and intermittent loss of power.

[Musky@RG]

Hey guys, I have an odd scenario and was wondering if anybody else has been through this:

Mods to the car:
- long tube headers and full exhaust with no cats
- 2018 intake manifold with IMRC still functioning
- JLT intake

I tuned this car a while ago with the IMRC locked out and everything went fine as far as power but the driveability suffered. The car is back now with a new manifold which has a functioning IMRC system. The driveability is much better now however under wide open throttle after 4500rpm the car seems to lean out and I can see the Fuel trims increasing up to redline and it is actually running much leaner. The equivalence ratio commanded started dropping in value as well. When I tuned the car on the dyno previously afr commanded and actual afr were matching perfectly. I did another power pull and this time the car felt like it had no power and the fuel trims were virtually zero and the knock retard value stayed at zero (instead of negative values which adds timing) I'd like to add that I tested the fuel pressure and it was holding a solid 60psi.

I've attached a copy of the tune as well as the 2 datalogs I just did on the street.
Any help would be greatly appreciated,
Thanks
Cameron RG Tune New Manifold with valves New.hptenrichment 3.hplenrichment 3 felt slow.hpl

[Thatwhite5.0]

SO locked out the car ran good wot with bad drivability down low. Now your problem switched ranges. Your IMRC's are closed, you have good drivability but top end sucks. Sounds like they're not functioning correctly. Try using these values in the IMRC tab.

imrcconfig.PNG

[Musky@RG]

Ok thanks. I will try it out

[Plimmer]

You can log imrc position with scanner. It logs the voltage at the position sensor, so you’ll the the change when it’s open or closed

[Plimmer]

Actually, just looked at your log, as Thatwhite5.0 said on the slow pull your IMRC was stuck closed. If the setting changes he suggested doesn't work, then I'd suggest you double check how you've routed the vacuum signal to the IMRC.

The IMRC's are pulled closed by vacuum in the intake when on part throttle. They should spring open when you go WOT,at least that how my GT350 manifold works. So if the stay stuck closed at WOT, then you've got some one way valves plumbed incorrectly

[Plimmer]

For fueling, you could try change the air charge multiplier in Speed Density. You'll have to check what mapped point you are running in when it goes lean, and then try increase the multiplier at that point. I had a similar issue and making the multiplier flat instead on decreasing with rpm solved my problem.

[Musky@RG]

SO locked out the car ran good wot with bad drivability down low. Now your problem switched ranges. Your IMRC's are closed, you have good drivability but top end sucks. Sounds like they're not functioning correctly. Try using these values in the IMRC tab.

imrcconfig.PNG

This worked! Everything now runs as it should. Thanks everyone for your input!