Truck feels low on power 94 4.0 5spd
OK so i bought a 94 Ranger that had a bad clutch. I replaced the clutch, flywheel, and slave cylinder but then messed up one of the manifolds so they were leaking at the y pipe. I then replaced them with headers and put new o2 sensors on, and gave it a tune up-plugs, wires, and fuel filter.
So after all this it still feels like it is low on power. it has a real hard time getting to 3000 rpms while driving in any gear but every not and then it does a little stumble and it just comes to life and i have power through that gear til i shift then it is powerless again.
I am kinda getting frustrated with it so any input would be greatly appreciated.