Rough start when cold too much fuel and air?

Ok. 1991 3/4 ton 2wd chev suburban 5.7l tbi 180k miles
ran great up until a week ago.
went to start it and a loud hissing noise eminated from tbi. Also seemed to be putting in way too much gas. Idles and drives really rough when cold. Coughs and sputters and smokes until warmed up then runs fine.
I originally was told it was the coolant temp sensor so I replaced that
replaced: coolant temp sensor- no change
replaced throttle position sensor- no change
replaced map sensor- no change
replaced o2 sensor- no change

removed and cleaned vaccuum openings on tbi - no change
no vacuum leaks noticed.
throttle plates are not sticking or worn
new fuel and air filter less than 5k miles ago
allways changed oil on time if not before

once it warms up- it runs fine but a bit rich. No ses light

however! If I unplug the coolant temp sensor all the problems go away. Except I get the ses light blinding me.
all parts were replaced with new parts
cap and rotor, wires and plugs look fine and were new 9 months ago. She allways runs cool and has never overheated.
also checked connections and wires on all replaced parts and they seemed fine.

please help! This problem just SUDDENLY started (she ran like gangbusters 2 days before. I went out of town and when I came back and started my baby this all began) and im too poor for a mechanic.
im out of ideas the last thing I can think is the ecm
also replaced the spark controller in the distributer a few months back.