Just purchased the 87 regal t-type 2.5 weeks ago. Engine only has 1,500 miles on it. Street roller cam in it. TE-44 new turbo w/programmable racing chip. Took a vaccum gauge reading and it jumps all over the place from 20 to 10. Idle jumps around alot to as low as 500 then konking out. New PCV valve. IS it a valvetrain problem? possibly a rocker arm stuck open. I don't know? Any suggestions?