P0300 -junk plugs (chalky/damaged) idles at 2500rpm and white smoke after repair

Question

1997 Grand AM gt 3.1: started to hesitate pull three plugs all chalky and electrodes damaged. remove coil pack and wiring pull back three same result. replace all plugs reassemble inspected all wiring retaped all connectors good condition all pins clean all reassembled correctly and chkd several times. ohm wires all in spec. coils in good condition. found no other issues while it was apart. replace tstat. fill coolant. started ran rough and dropped out did twice more then smoothed out then jumped to 2500rpm and 15secs later white smoke out end w/ clear water also. try several times same result right to 2500rpm and smoke and steadily increase in rpm. repair rubber section on 1/8 line (rubber cracked) and pcv tube broke in half sealed w/ heat shrink and silicone. disconnect batt remove all connectors that had apart for plug repair wait reconnect all secure reattach batt. let sit, started same result. had codes p0107 MAP low volt (chk had spc volt, clean out MAF) 90162 02 bank2 sensor 3 had one additional code from p0300 p0420 TWC low eff. had intake and head gaskets replaced 20000 ago after bought car. any suggestions on next step or to chk intake for leaks helpful thanks