4AGE lean condition

[yotatoy]

whats up everyone, I just disassembled my '87 4AGE to replace the head gasket. The engine has been running very lean. The only modifications done to the engine are as follows:
-header & full exhaust w/ no cat.
-free flowing air intake
-disabled EGR system
I am not sure what caused it to go lean but I have a few ideas. either way it needs more fuel. What are some things that you guys have experienced with these same type of mods?
and what are my options?
-Bigger injectors?
-more fuel pressure?
-fuel computer piggyback system?
-colder spark plug?

Any help is great, Thanks

[94_Rolla_Guy]

i would say your intake / header / disabled EGR are compounding to create the problem, my headers alone put me into a slight lean condition....


also might wanna check that your AFM is working right and that there are no leaks between it and the throttle body.


if you can find one the easiest thing to do would be to use an adjustable fuel pressure regulator to increase your fuel a little, or something like a S-AFC

[toyotaspeed90]

check the vacuum line that leads to your fuel pressure regulator....