With the twincam 6 you've gotta suspect the valve train first - timing chain stretch, cam lobes & rocker arm adjust, etc - assuming loss of power is what you've got.

And those are self torquing adjustment bolts under the acorns. Their self torque threads usually begin to wear out at/near 125k miles.

Btw, surfaces of rockers should be ONE color metal, if they are worn exposing patches of darker metal underneath then replace them immediately, even with good used rockers, before they eat the camshaft lobes.

Hell yes, if you want something to do - inspect the camshaft and rockers - critical items on the TC 6 cyl.

(edit: wait a minute - 58k miles in 25 yrs huh? Take a long haul road trip at 85-90mph with injector cleaner.... FI system is probably varnished with 1/16" of shellac.