One item that is critical, for efficient which old Roky seemed to
overlook, as most folks do, is the throttle positioning switch which
tells the ECU when and where the the throttle is where.
This should be one of the first items to be checked, adjusted or
replaces in a situation like this.
The plastic operating cam does wear out after so many miles and
completely changes the fuelling situation from off idle, or at WOT.
Very few folks even think about this device which in most cases should
be the very first item to adjust or replace.
If you Rocky just take the throttle wire with you hand, and just crack
open the throttle, and if you don't hear an immediate "CLICK", you have
located the problem.
Once every 100,000 miles this item at least should be looked at,
adjusted, and replaced if needed.
Then start fishing for problems at the coolant temp sensor,  the oxy
sensor, and possibly the FPR.
I believe the fuleing problem isn't really there.
It's part of an electrical engine management system that is causing the
problem's.