Hi all- Yes I am a newbie here so go easy okay .....So I just replaced the coils and plugs on my '04 Mazda 6 Sport Wagon. (I suddenly started getting a blinking CEL with a P0302 while driving on freeway but engine was running smooth) I replaced the plenum gasket set and sprayed out the throttle body. Also replaced the air hose as I cracked the small tube for the crankcase ventilation on the air hose. Everything back together and engine is running with no codes. I noticed in the Haynes manual that when the battery has been disconnected and the intake manifold removed and replaced that "the PCM has to 'relearn" it's settings for optimal performance and driving". But the book does not give any further details on how this is done. I've seen a whole lot of posts about how to 'reset' the PCM and most seem a little ridiculous. Is there a specific procedure needed to reset the PCM?

The repair went fine, it idles a little rough and the automatic transmission seems to upshift and downshift a bit roughly when driving but gets better after a bit. Have driven it about 20 miles or so. Temp is fine and everything seems to operate normally otherwise. I am thinking I may have a poor vacuum connection somewhere but wondering if this is due to the PCM needing to be reset? Any thoughts would be appreciated

 

When the battery is disconnected, the PCM loses it's learnt values, The PCM learns the operation of the engine overtime, making small adjustments for wear n tear and deposit build up in the intake.

Disconnect the battery, Clean your throttle body and MAF sensor, reconnect battery, turn off AC, heater, lights etc, start engine and allow to idle for 5 minutes. Job done.