my oil gauge reads low pressure at idle,then loss of ecceleration whatcould caus on 1995 Pontiac Bonneville

switched out starter,sonds like its siezed but its not

2 answers 2 comments
does the motor turn??

it tries 2 but not fully over i was told it might b a timing belt is there a way i could check without taking the cover off
3.8L engine is pushrod with chain , not belt. What condition is battery and ALL connections and wires? Has starter been tested for excessive draw? Mass air flow meter checked for restrictions/leaks in intake for loss of power issue?
you may have then beginning of an eng siezing up. can you turn motor over witha socket on crankshaft bolt?