Howdy,
First off - 89 IROC, 350 TPI, 150k miles, all original, been well maintained. Runs and drives nice.

Starting problem (normally starts fine), generally after being driven then sitting for longer than 15 minutes. Will crank fine, may try to fire briefly, but willl not start. I can try cranking it for 45 minutes, giving it different amounts of throttle - but it will not fire. Will start right up with starting fluid - or - by unplugging a few fuel injectors. I can unplug some fuel injectors (no starting fluid used) and it will start up and idle rough, i will then plug in the unplugged injectors, idle smooths out, and off i go. I have done this exact senario for months, more than 20 times (i often drive another car).

So - injectors going bad, or something in the injector driver circuit ?

thanks,
james evans
www.z28evans.com

 

Maybe vapor lock, leaking injectors, fuel pump weak, ignition coil/module/pickup coil weak.