Well - after countless hours of researching these forums I decided to start replacing the small stuff to fix my nasty idle, low RPM hesitation, popping, and stumbling:
fuel pressure regulator adjusted to 44psi, o2 sensor, MAF sensor, plugs, wires, coil, TPS voltage regulator, K&N...after all that - still had the same problem. I ran consistent 14.20 in 100% 1987 original trim, and 14.00 after those mods. I though "okay..it has a few quirks, but it's obviously running consistently faster than 14.30, so i can start modifying it i guess and hey - i gained .2 replacing all that small stuff anyway" ...my ultimate goal is a consistent 12.50 car that i can drive daily, and take across country on road trips on a whim without needing to throw a toolbox in the trunk ;)
Since the car was running better than 14.30-14.60 on stock, orig. 1987 tires, i decided to take the plunge and call Rick Harper http://www.harpersracing.com
Real cool guy - and knows his stuff.
I ended up ordering 009 injectors, Red's 93 chip, Terry Houston downpipe, Walbro 340 w/hotwire, Nitto 275/50/15's, and my machinist buddy made an adj. fuel pressure regulator and trick adj. wastegate (its not like the diagram on this site..it's much better - no need to unclip the rod).
This weekend we had time to install just the injectors, adj. regulator, adj. wastegate and chip.
WOW! This thing acts like a completely new car! Idle is smooth as silk, ALL my idle, hesitation, popping, stumbling problems have vanished, and WOOHOO! This sucker HAULS! I cant believe the difference just those few mods made..id say i have EASILY knocked a FULL second off my 1/4 mile time with just a Red 93, 43# 009's, adj. regulator, and adj wastegate. The T.H. downpipe and 3" CAT comes in next week, and i will install the fuel pump then as well. Tuesday is test n Tune at the track, so i'll know what i run then.
..just wanted to re-post for anyone who was interested..the 43" 009 injectors fixed all my problems, and with Red's 93 chip - the car runs 100% perfect. I have it set for 20lbs of boost right now on 93 octane, and it gets 5-8 spark knock counts over a "simulated" 1/4 mile at WOT for about 15 sec. I can hear it when it reaches full boost (18-20lbs).
Is that safe still? I know i will need higher octane to run that much boost, but what is the best way to get rid of it besides that? I have R43TS plugs gapped at .035...would 42's get rid of it too? I hate to kick down to 17lbs boost when i can run 20 with a few spark knocks over the course of a 1/4 mile. :P It's like giving away a child..it kills me to turn DOWN boost 3lbs!!!
Input anyone? BTW - get the 009's with Red's 93!! You wont believe the difference it makes on a stock GN!