If after adjusting your valves with the engine at temperature it still will not idle, it could be a vacuum leak as you guessed. If it is not that then check your idle mixture screw. If you turn off the choke and the truck just dies with little to no hesitation it's too lean. If it takes a couple of seconds and you hear it 'drowning' with black smoke out the back you are too rich. Set your idle mix a little rich so you get good off idle response from the engine. A lean idle will stall at stop lights when you punch the gas to go. Hope this helps. Good luck!


'52 Chevrolet 3100 (Rodded of Course)
'97 Eagle Talon TSi(Turbo Baby!)