Well my 1988 z 5.7l tpi with which I have redone twice aii the upper intake gaskets and replaced all the sensors again. The car will idle to an extent now and just stall. Well the significant popping noise in now enhanced by a whistling. Well I have started it and the car will smooth right out when opening up the throttle and then comes back down to idle anf falls flat fust eventually stalls. I believe I have a major vaccum leak somewhere but I cannot find it. Rechecked all the plugs and all ignition components are new. I have one other alternative to replace the original throttle body back on the car. I do not know any advive thanx Tim

 

Did you hook up the small vacuum line on the bottom of the throttle body that goes to the fuel pressure regulator? That one's easy to miss/forget. Also, does the heater control valve have the vacuum line connected to it? Power Brakes connection? PCV valve? Hose between the passenger's side valve cover and the TB? EGR valve vacuum line to EGR solenoid? Plenum to EGR solenoid?

That's all I can think of right off hand....

 

Options:

1) Use a rubber hose as a stethescope to narrow down the whistle location.

2) Use a propane torch, unlit, just venting the gas. Wave it slowly around the upper intake (TB, plenum, intake manifold), and when the idle fluctuates, go back over to narrow down the spot. Turn off the gas, look around and you'll see what you missed.