what are some basic signs of an intake leak? cpu controlled 305 with egr started experiencing some problems not sure if its just a broken /unhooked vac line or something more serious .(cold) will not idle without constant pumps of the gas ,(warm) idle is very rough and really solw- idle speed screw turned all the way in . it will jump up with some gas pedal but dive down and stall . also power assistance for the brakes seems to cut out when crusing to a stop. ive only gotten a chance to check vac lines , and pull two plugs tonite - #1 center electrode was clean , outer edges were dark , & #3 look almost fouled . ive heard there were some tricks to finding such leaks just cant remember . sorry about the lenght of this, any help would be great

 

The old trick is to put both of your hands over the top of the carb to restrict the air going into the engine. Slowly restrick more and more air. If the idle smoothes out and rpm goes up, you have a vacume leak. If it starts to die without speeding up, then no leak. If it leaks then put the air cleaner back on. Carfully you can spray small squirts of starting fluid around the intake gasket and vacume lines. If the engine speeds up, there is your leak. Make sure there are NO wires arcing or shoot it on a hot exhaust manifold. Have a fire blanket or fire extinghisher handy. Saftey glasses/googles would not hurt either. Later>>>>>>>>>

 

im going to have to try that staring fluid thing - i finally got it to idle (cinched the air tube hose clamps tighter) and heard a hissing nut was unable to determine where exactly its coming from . also noticed rpm flutter itll start to raise then lowerquickly but now without stalling . stupid question - would a blown out muffler have anything to do with it (back pressure for the egr ?)

 

i fixed it . i tried covering the carb , and had the r's increase but ws unable to find the leak. so after i got home from work i removed every last vacuum hose , the quadrajet and the intake and replaced them with the setup i had on my Z , edelbrock rpm , holley 650 and msd 6al every thing went together good , and after a major jet change evrything seems good . plus no more vacuum leak - thanks - scott