19924runneryota

92 4runner with new shortblock(toyota factory) and redone heads etc(all compliments of toyota's ssc head gasket campaign a month ago. It ran fine for a week or so, no sometimes it surges and has no power. It doesnt do it all the time but it also will clear up at 33 to 35 hundered rpms like throwing a switch. today it wouldnt even get up to 3000 unless in nuetral? any ideas