Nissan Repair: 93 hardbody low pulsing idle, chng, hardbody

Question
i have a 93 hardbody 4cyl 2.4l auto trans on the floor 192k miles. we jst replaced the trans with one frm a 96 with 99k miles on it. after doing that the truck had a weird idle issue. idle is low at a high 900rpm in park/neutral but usually goes as low as 600rpm. in drive when stopped its usually between 350rpm and 600rpm at best. replaced plugs/plug wires and air filter no chng. also the exhaust smells rich in fuel and check engine light is on. any help would be greatly appreciated.

Answer
Hi Andrew -

Sounds like the IAC (Idle Air Control) module is not working, however the best thing to do is to get the OBD and check why the engine light is on. If you get me the code, I can tell you exactly what it means.

I am also hoping that the 2 trannys are compatible. Perhaps physically, but may not be as far as the computer signals it requires.

Anyway, let me know about the code -

Hope this helps -
aloha
calvin