2.5L ('98-'01) Engine running very lean with NO check engine light(98 Ranger) (2.5L) (manual)

[Alam0]

Hello, my engine is currently running very lean with no check engine codes. Short term fuel trim reads around +35.9%
I ran a smoke machine and found no vacuum leaks.
A while ago it was actually running too rich (-23.4% Short Term Fuel trim )and now it seems to have switched around.
I replaced:
-maf sensor
-iac sensor
-ecm
-tps sensor
-Fuel pump and filter
-Fuel injectors
-upstream and downstream o2 sensor
Also my maf rate reads around 4.11 - 6.65g/s
I've been dealing with this for months now, I would appreciate any help

Update: after running the engine for a couple minutes it now started running rich again
Jumping around from 0 to -21.9%

 

[Oldman99]

Hello, my engine is currently running very lean with no check engine codes. Short term fuel trim reads around +35.9%
I ran a smoke machine and found no vacuum leaks.
A while ago it was actually running too rich (-23.4% Short Term Fuel trim )and now it seems to have switched around.
I replaced:
-maf sensor
-iac sensor
-ecm
-tps sensor
-Fuel pump and filter
-Fuel injectors
-upstream and downstream o2 sensor
Also my maf rate reads around 4.11 - 6.65g/s
I've been dealing with this for months now, I would appreciate any help

Update: after running the engine for a couple minutes it now started running rich again
Jumping around from 0 to -21.9%

Did you find the problem?