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


Joined
Jan 16, 2022
Messages
8
Points
1
City
Houston
Vehicle Year
1998
Transmission
Manual
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%
 

Attachments

  • Engine running very lean with NO check engine light(98 Ranger) (2.5L) (manual)
    ranger station high fuel trim.png
    135.3 KB · Views: 200
  • Engine running very lean with NO check engine light(98 Ranger) (2.5L) (manual)
    ranger station low fuel trim.jpg
    74.3 KB · Views: 148
Last edited:
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?
 

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