ive recently replaced my battery in my 04 rx8.

my car starts up perfectly and runs like normal, but when i get to a red light my rpms drop all the way to 0 and my car just stalls. im aware that this is because my rx8 is re learning the fuel trims

my question is that its been about 3 days and this problem is still occuring, how long does it take to re learn its trims? and is there anything i can do to make it learn faster?

 

It needs more time at idle. Start the car, let it idle warm, and then let it idle for another 5-10 minutes. The idle trim should have stabilized enough at that point to prevent stalling.

 

thank you
i havent let it sit at idle very long yet,

i drove it like heck and thought thats how it would re learn its trims
do you recommend i remove the connector to the battery and start fresh?

or just let it idle?

 

It helps to remember how the fuel tables work: (this is the AFR target table that the fuel trims are trying to hit, but all the tables work the same, unknown if this is a modified table or stock, that part isn't really relevant, just a visual assistance)


It will only build a fuel trim in a cell that you spend time in. The more time you spend in a cell, the more accurate the fuel trims will be (assuming you have everything healthy). So driving at not-idle won't spend time in the idle cells, so no fuel trim will be built.


Reset or not is up to you, doesn't matter much.

 

Question:
If I had a bad o2 sensor, and reset the fuel trims, The ECU wouldn't be able to relearn the trims correctly, right?

My car is having the same problem, but it's been going on for close to a year now. Stalls at highway speeds (50+) when clutch is in, or in neutral

 

Well stalling could be many things. You need to properly troubleshoot the issue.

Engine----> Symptom Troubleshooting

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