very lean condition at idle

[TurboCajun]

I have been working on a friends GN, after fixing all the exhaust and vacuum leaks and also putting in a adjustable fuel pressure reg to get the pressure right, BLMs at idle go to 150 , as soon as you give it a lil gas BLMs go to 128 or so. this is 100% stock 87 drive train except for translator and new maf, IAC seems to be adjusting the air, it gives me 44 code if I leave it idle for awhile but goes off after playing with throttle. Any ideas?

[TurboCajun]

its an 85 with 87 drive train, seems to have well over 100k miles but it is unsure.

[Steve Wood]

the maf reads 5-6 at idle?

Sounds like a classic vacuum leak.  Have you checked around the base of the plenum and the base of the vacuum block?  Around the throttle body to the plenum and around the iac to the throttle body?  No leaks in the pipe or hose to the turbo?  No broken vacuum line to the vacuum check ball or the ac?

[TurboCajun]

maf reading is good, I have been over all the vacuum lines and sprayed carb cleaner everywhere. guess i will have to look over the intercooler piping and intercooler more, it sounds like there is a leak just can't find it. sounds like it is in the front drivers side.

[good2win22]

There is a sneaky vacuum line that runs in front of the driver's side wheel well to a vacuum canister.  It runs next to the vacuum lines that go to the cruise control and then down to the canister.  I searched all over for every possible line and this vacuum line seems to get more exposure to the elements.  Hope this helps with your leak. 
 
I just ran through this on my limited and a new oring on the fuel rail inlet and a new oring at the FPR outlet solved my issue.

[Steve Wood]

check the egr and make sure there is not a tiny leak around it as well