88 80Q won't start or idle when cold unless you crack the throttle

[MXHOWES at aol.com]

I posted this question a few months ago and only got one reply suggesting a  
stuck air meter plate which wasn't the problem any other suggestions?
 
My 88 80Q was parked in the garage for 6 months undergoing a  heater core 
transplant. I just got it running again but I picked up a  strange startup 
problem. The car will not start when cold unless you press  down on the gas just the 
smallest amount. If you crack the throttle, it will  start right up, if you 
take your foot off it tries to idle at about 400  RPM.  When cold you can make 
it idle ok ~900 RPM by applying a little gas  by foot, the mixture is correct 
because no mater how cold it is it idles  smoothly (with your foot on the 
gas). After a few minutes (or miles) you can  remove your foot and it will idle as 
normal. When hot, just  hit the key  and it starts up right away.  The heater 
core replacement requires a  complete dash removal and lots  of wires were 
disconnected. I didn't have  to touch any wiring under the  hood.
The car started perfectly when cold  before the heater core operation and 
still runs great, it's just that something  isn't right.   Any ideas?
Thanks,  
Jim