Mysterious misfire after Reconnect battery

[TERRYDIABLO]

I DCed the battery before doing water inlet housing reseal. After reconnect the battery, the 4r misfired for the first time after Reconnect battery. and today it misfired one time again. they both happened when cold start.

checked battery terminals, checked the MAF sensor plug, they are both fine.

Does the ECU need to relearn everything and cause misfire possiblely?

the vehicle runs fine after it's started.

No CEL

(4gen 4runner)

 

[TERRYDIABLO]

Once the 4r started, it runs fine. Took a 30 miles test drive and didnt notice any problem. The problem only occasionally happen when first start the engine: twice in about 15 starts.

 

[demarpaint]

It shouldn't misfire, but then again the car has to re-learn since the battery was disconnected. It can take some time. Give it a week and see what happens. I think you'll be fine.

 

[JHZR2]

I find it hard to believe that misfiring is the result of something not learned. Unfortunately I'm more of the school of thought of user error, that wasn't noticed (we all do it). Something got brushed or moved in such a way that there is an intermittent issue. I just don't see how a computer is going to learn to prevent a misfire on one cylinder, unless there is a mechanical issue in it.

 

[babyivan]

Originally Posted By: demarpaint
It shouldn't misfire, but then again the car has to re-learn since the battery was disconnected. It can take some time. Give it a week and see what happens. I think you'll be fine.
+1

Relearning is a real thing.

Misfiring is not that uncommon during the process.

Give it time to relearn and all will be good.

 

[artificialist]

Cars can do a variety of weird things after the memory of the ECU is erased.

It may take 3 days of driving to make it go back to normal.