Well I just set the timing on my rebuilt chevy 5.7 1999 suburban. It still runs sluggish when I accelerate and idles nice when it’d parked. I rebuilt the whole part part of engine. This is what I did notice when I cleaned under the lower intake manifold where the fuel injectors plug in. Here is a attached picture. Let me know what you think…
You’re talking about the pitting, I presume . . .
It’s a factory aluminum intake, I presume . . .
Do NOT machine the intake to remove the pitting. Only remove any traces of old gasket. A scraper and/or a brass brush will suffice.
As for reassembly, you may want to put on a SMALL amount of rtv on the pitted areas. This is only to help the new gaskets seal.
FWIW . . . this is a very common situation on aluminum manifolds