Ok, what causing this problem???
 

Hey guys, I have a 1987 2.5L 8V that is having a few issues. I bought the car out of a few years of storage in a garage and went full through it. Mechanically, the engine's solid, fuel pressure, compression and ignition are right on spec. The PO had done the head, timing and tension were right and I had run out a compression test with the first 3 cylinders at 145, number 4 at 143-plugs, wires, cap and rotor are new by PO and show it. The gas tank was full of water and I R&R'd it, new filter, blew out the lines, resealed and cleaned the injectors. Some of the primary vacuum hoses were crack, so I bought new replacements from the Bird here, had a new ICV on the shelf and installed it with the new hoses. Here's the rub. The car starts on the first tap of the ignition but jumps immediately to 4000 RPM, (sounds good, no misses) and with a tap on the gas, drops back down and stalls out. Can't seem to make it hold an idle at all.

I'm going to test the throttle positioning sensor tomorrow but did clean the contacts. Don't think there' any vacuum leaks, new hoses AND CLAMPS. This one's fight me-any one have any thoughts????

Hmm... possibly a DME issue?

Pull the throttle body and check the butterfly? Maybe there's a vac line unattached? Whopping great hole in the ICV? And one that fooled me: check all your intake manifold gaskets.

Massive vacuum leak would make sense.

I had a bad j boot issue one time that kind of sounded like that. As you know they love to crack underneath. Just a thought...

Check the vac line from the brake booster to the underside inlet on the intake manifold.

There's a T-fitting under the elbow part of the j-boot that's out of sight. It may have fallen out. It's attached to the ISV and the venturi tube. Also look at the fitting for cracked condition.