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The 4.6 in question is in a late '93 Crown Vic, ('94 firing order), but here goes. I removed the intake manifold, replaced that water pump hose that runs under the intake (who thought up that one) replaced the manifold gaskets and put it back together. When I fired it up it dies immediately. After checking the maf, firing order, looked for vacuum leaks, I discovered if I place a shim between the linkage and the throttle body, the car will keep running. So my conclusion is the IAC valve. The question is this, is there a simple way to test this without replacing it? The car is not mine, and my buddy is trying to find the cheapest way around this. The car ran relatively well before the hose blew, but it seems strange to me that it would develop this situation during it's down time. The project has been a 6 week one since either I didn't have the time or he didn't have the money to move forward. Any ideas? Oh the CEL is burned out, but I reset the computer with no results. I took this on as practice for when, if my plastic manifold goes on my bird, but boy I'm ready to wrap this one up.
 

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First check the conection to the IAC and make sure there is power going to it. At old age the wires to the IAC may be briddle and could have an internal break. When moving the harness' around during the job, it could of caused this. If there is power going to the IAC try tapping it with the hammer while trying to start it. If it starts up and runs fine, then you have a sticking IAC and the only real fix is replacing it!

Recheck for vacuum leaks! When the car is running, use a small bottle of propane with a hose on it and spay some gas around the intake gaskets and all the vacuum lines, etc. If the engine surges then you have a vacuum leak.

Oh and if you have access to a power probe, that is an easy way to test the IAC.

Good luck!
 
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