FU_I_AM_UltraZ

iTrader: (20)

Got a 98 trans am. clock reads that there is just under 90K miles on it, but car has salvage title do to suspisous odometer misreading. anyway. cold idle oil psi is good, but when warmed up drops to 25-30 at idle. when driving temp. is at 165ish but in traffic goes to 215. i think that might be cause the cooling fins on radiator are clogged on some areas with debris. from what i believe is cylinder 8 cause it sounds like from rear of motor on driver side is a slap/knock sometimes... should i switch to a 10w30 from 5w30 for time being until i change out oil pump or are the bearings becoming shot?
Thanks!