RB25det....won't stay running fuel/spark

[Florida240sx]

rb25det in a skyline r33Was running fine and then went to start and wouldn't fire....Got it to fire now..... Have an AEM wideband and aem standalone on it. Aem wideband shows very lean under 3000rpms... above 3000 IF you can get it there it hold fine around 11ish.. all the way to redline. But instantly below 3000 it goes lean over 19A/F gauge doesn't read no more By tapping the gas can try to keep it alive under 3k at 2800rpms acts like mafs is bad but if able to get above 3k it purrs like a champ....Any ideas? Igniter and coolant temp were replaced today, along with new sparkplugs and fuel filter.

[Sil240]

Maybe your AAC valve is stuck open??

Have you checked all of your vacuum ports etc. for any hoses that may have blown off??

[Florida240sx]

fuel pump ground