Chrysler Repair: Chrysler Dynasty 1990 keeps stalling, positive crankcase ventilation, butterfly valve

Question
QUESTION: Hi mister, first of all thanks for taking some time to read this and reply, it's much appreciated.

So here's my problem. I have a 1990 Chrysler Dynasty with around 170 000 km, I just paid 300$ for repairs on the car (the intake needed to be fixed because it was leaking prestone and the fuel pump needed to be changed also) stil after this I still have a problem, the car is stalling on stops and when i'm waiting at trafic lights. It used to be much worse before the fuel pump was changed, I tought the car would not stall again after, the mecanic who changed it also.. we were wrong it keeps doing it (only less than before) It's very annoying, can you help me please?

Thanks in advance!

P.S. I checked for the code as you mentionned in a previous article, i believe the code was 12? It flashed once, had a pause then flashed twice then flashed 5 times then 5 times again. If this can help..

ANSWER: Hi J.-F.,
You didn't mention which engine or where the vehicle was initially sold so I can't be certain of the pollution control devices that might be installed and which might be the cause of your problem.
In any case, my suggestion would be to clean the butterfly valve plate (both sides) and the throat of the the throttle body, and also clean the by-pass idle air passageway, using solvent and q-tips. Then see if that has solved the problem. If not, then I would check the positive crankcase ventilation (pcv) valve. Finally tell me where the car was sold originally and which engine you have so that I can identify some other component that may be causing the poor idle situation.
Roland

---------- FOLLOW-UP ----------

QUESTION: Sorry I forgot to mention, the car was sold in Quebec, Canada and it's a 3 liter engine.

Answer
Thanks,
Take a look at the sticker on the underside of the hood that shows you all the hoses that are attached to the intake manifold. Follow each hose to its final location and look for cracks/leaks or faulty item at the far end of the hose. Any source of air entering each pathway will lean the mixture which will kill the idle. In the meantime do check out the throttle body throat/butterfly plate/idle air passageway. Of course keep checking for fresh fault codes.
Roland