1990 No Up Hill Power?

[crazy-101]

I have a very similar problem on my '95. It will cut out and chug going up hills and shake almost like a misfire just going down the road and when accelerating it will almost gain and loose power at regular inter voles. Did a vaccuum test and the needle was bouncing around. Code in the ecm is to lean but is running to rich. Has exhaust leaks in front and behind the o2 sensor

I have replaced:
Fuel filter
Distributor, cap, rotor
injectors
injector connectors
tbi full rebuild
egr valve and solenoid
ignition coil
changed plugs twice burnt plug on the #2 cylinder
temp sensor x 2
intake
intake gasket
oil pressure switch
idle air control valve

I have been told that I will need to pull the heads and have them machined and/or a valve job done. The old intake manifold was warped and replaced in April. May be your only option to do heads as well. If anyone else has a suggestion please feel free to speak up.