somewhere long ago i read where someone recommended pulling the vacuum line on the fuel pressure regulator on an 80 to test it. what i recall is that you are supposed to note an upward rpm change at idle when you do this. that makes sense. my 80 does slightly surge when i yank that line. my b-i-l's 1990 4runner v6 does nothing although there is lots of vacuum pressure. can i conclude his FPR is bad or is more needed?