Jeep Repair: 1997 Wrangler, stalling and runs rich, air induction system, pcm software

Question
QUESTION: I have a '97 Wrangler 4.0L, 6cyl that has a K&N Air Induction System installed.  My check engine light will come on and go off in between turning engine off/on.  Took it to mechanic and he said he could not get a read on computer because the after market K&N system.  While idling, the engine has stalled.  It sputters while accelerating slowly and smells rich of gas.  If you punch the accelerator it does not sputter.  While driving at a constant speed, no problems. But if I let my foot off the gas it smells rich.  Any suggestions are greatly appreciated.

ANSWER: go to a different shop and dont go back to the one u just went to.  U have a Kn Filer  its an air filter correct? What would the air filer have anything to do with a computer not being able to read codes.I live in the Atlanta area I would be glad to look at it for u.

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

QUESTION: Unfortunately, I do not live near the Atlanta area.  So regardless of aftermarket parts, the computer should be able to get a read?  I have the K&N Air Intake System and Filter.  From K&N - Description: Fuel Injection Performance Kit (FIPK), Generation 2, Replaces Entire Air Intake Tract, With Filter.  Do you think this is too powerful for the Wrangler and could be causing the stalling and running rich?  Any advice is greatly appreciated.  Thanks so much.


Answer
I take it u dont know about speed density systems do ya well here is a small cap  The rich and lean that u may think of is not right. The system will add more fuel if there is to much O2 trying to get it back to 14.7 to 1   so if the system is in fact rich u have a  vac leak sucking in more air and suppose to or an exhaust leak will do the same. Your KN filter will not allow more air into the system because the throttle body that it goes into is not any bigger  understand? Any ODB2 scanner should be able to get into the PCM. There is a TSB to update the PCM software for trouble from after market shops to read the computers. There also is a recall on some wranglers and jeeps for a cat and PCM update  whats the last 8 of your vin and I can find out for u .