I've been a reader of the forums for a long time, but finally made a username. I cant seem to find a post that matches my cars symptoms, so here goes.

I have a 1986 Iroc-Z with a tuned port injection motor. I just got the car a few months ago and have done a full tune up but I'm having issues with it. I got the car from an older guy who bought it new from the dealer in 86. The title still had 40 miles on it. The car has 126,000 He said he had the motor replaced at one time and by looking at the valve covers with 4 bolts at the corners it is either a 85 motor or has older style iron heads on it. It sat in storage for 4 or five years without being ran. I have changed all the fluids and the fuel is fresh premium gas. It has a 700r4 transmission.
On start up, I have to press the gas pedal slightly down approximately 1/4 of the way to get it to fire. Then after a cranking or two it will start and run fine. After it gets warm if I shut it off and restart it, It fires right up without pressing the pedal but wait a few hours or overnight and the problem reappears.
The other issue I have is it stays in high idle for longer than it should. It kicks down after a while (a min or two) to where it should be but after restarting it even when its warm, the idle goes back up high and takes a while again to come back down.
Any ideas on where to look from here?
Thanks!

 

I wonder if the Cold Start Valve isn't working? (9th injector)

You might be able take things loose, remove the valve, tighten things back down with the valve angled away with a few rags where fuel would squirt...try to start it (when cold) and see if fuel is coming out of the valve.

 

First check fuel pressure & bleed down rate.

 

Thanks for the ideas, the car runs great after it fires up, it doesn't stumble or miss like low fuel pressure or clogged injectors. No performance problems after it fires, it just takes 1/4 throttle on the pedal and a few times cranking before it starts. It will pop, and slowly start firing then clean itself up and idle perfect after 2-3 seconds. Then it will idle up to 12-1500 rpm, then ramp down to 750 after a min or so.

Are the 86 computers the same as 85?

Cycling the fuel pump seems to make no difference either. If it was low pressure then I would notice it when it was running and if it was draining back into the tank, wouldn't cycling the pump eliminate that causing it not to start? Ill have to wait till I can check the pressure at the rail till I can borrow a gauge.
I was kind of thinking about the cold start injector system too but have not had the time to check it out. By the way it shows no codes or check engine light. It does light up as you crank as it is supposed to then goes out and stays off.