I have a 1997 Eclipse GS, and while driving it if i shift into neutral the car just shuts off. I just installed an sfmu, 440cc injectors, crower cams, aem cam gears, new fuel filter, fuel gauge (reads 20psi at idle) i'm running 10psi of boost. I have an safc but everything is at 0. When driving though not in neutral the car runs mint. Also when i first turn it on it doesnt want to idle unless i give it some gas for about a minute then it will idle fine. Do u think it could be my IAC>? Before i installed all this stuff it wouldnt shut off when i shifted into neutral but i did have to hold down the gas for a minute or so. It is also backfiring a little when i rev it about 4 grand and let go on the way down it backfires. But I also have a leak in my downpipe that I havent fixed yet.
Thanks In Advance,

if the car doesn't idle from a cold start at like 1100rpms then your IAC COULD be bad.

and once the coolant warms up it tells the ecu to drop the high idle.

I think its the vaccuum screw on the sfmu, its turned in all the way, i think its cutting out fuel when i let off the gas. How much psi should my fuel drop to when coasting in neutral if i at idle i am 20 should it stop at 20 when coasting?

whats the vacume in/hg when decelerating?

20psi of fuel sounds fine to me

that exhaust leak could make it die when you decelerated, but it sounds like the IAC to me...just pull it off and clean it with carb cleaner and see if that helps. gotta start somewhere.

Exhaust leak is your backfire. If you take a big rag and can cover leak do the 4k thing and the back fire should go away.
MB
Wait a sec. I didn't mean to leave the rag on. Just use your hands (with gloves) to hold the rag in place to TEST to see if backfire goes away.