You should have both heads rebuilt.
I didn't do anything with my injectors during my rebuild.
Do you have the new larger orange o-rings for the intake manifold to TVG's. Thay should be replaced and you should tighten all the fuel lines under the intake.
227,000miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. CHECK your oil, these cars use it.
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