hello first timer in need of help
 

(my actual question is below this info is just background)
hello, Im Saint, i am a Aircraft Mechanic for Quest aircraft Co. in Sandpoint ID. i like your forum, lots of good info, ive been searching around on here for a while for clues to my problem. my wife and i just got our first 4 runner 94 v6 with head gasket issues. got the head gasket problem fixed but there is another issue. it wont idle... starts and revs up to 1000 then dies. but if you give it gas it can revs up to 5k it sounds good and runs fine. then comes back down ... and dies. if you drive it down the road and it gets a chance to warm up... it dies. i was able to advance the timing and it will stay idling once its hot. then i disconnected the Fuel Pressure Regulator and itll stay idling at start up. so i thought the FPU VSV was messed up and that i would be able to turn the timing back to spec.. put it to 10 btc and it wont Idle anymore. im to the end of my rope on this its starting to get beyond my experience on cars. useful knowledge would be greatly appreciated.

things ive done. (to solve this problem)
checked ECT sensor. and replaced.
checked TPS sensor. its functioning within limits.
checked vacuum lines. all seemed routed properly.
advanced timing so i could drive it.
disconnected the FPR vacuum line to check vsv. and it smoothed out considerably. and was able to idle.

so my question is. what failure can be hidden by advancing the timing and raising the fuel pressure to the injectors?


thanks

Saint.

Vacuum leak? Brake booster?


Try and run it with the brake booster line plugged. If that doesn't work spray around the intake and throttle body with WD40 while it's running to help look for a vacuum leak.

I have no idea if this will work but it cant hurt. Run a can or two of seafoam through a couple of different vacuum hoses so that it will hit all cylinders. Also turn the idle adjustment screw to just past 1000rmp and see if it holds a idle after that, even if its high and holds, it might be able to give you another clue as where to look. Dont get discouraged.