Suzuki: samurai idle problem when warmed up, emissions systems, stock carb

Question
I have swapped a 92efi 1.3 for my 88 samurai.  Since the swap the idle in fast in the mornings which is normal. once warmed up the idle lopes.  I dont have a tach so i dont know how big of change in idle speed.  It revs for about 3 secound and then falls on its face with a wierd noise.  i have changed the oil, vac lines, spark plugs, air cleaner and wleaned what i believe is the IAC vavle between the air cleaner and throttle body.  The valve sucks air and if i cover it with my finger the idles gets a little better. The code on the dash comes up 51 which is egr system and i cant pass smog in CA.  any help would be great im losing my mind.

Answer
First, make certain the egr isn't partially activated, and that the egr valve isn't stuck partway open.  Some of the injected systems have a position feedback on the egr pintle, and those, if faulty can cause problems.  Go to the Suzuki website and see if you can get a FACTORY manual, because all the rest are garbage when it comes to fuel and emissions systems.  I have factory books for my 87 sammi, but I don't have any lit for injection systems except for my 91 swift with a 1.0 3cyl.   Some of the dealers may not have thrown their 92 books out,yet, it's a thought..........P.S. Your stock carb is worth money The Weber isn't worth squat offroad, but the stock Mikuni style is worth some bucks
scotty