Rep Power: 0

I replaced a battery on a 98 Civic. After that, the car starts fine, runs fine for a couple of minutes, then starts with an erratic or searching idle... up and down, up and down.

It is not my car, I don't own a honda. so I am taking a guess here... vacuum/air leak, which causes a problem after the car warms a bit, car goes from open loop to closed loop and O2 sensor(s) kick in. If so, is there any obvious place to look, since I just replaced the battery and perhaps knocked something loose?

Second guess would be IAC... again, any thing to test or obvious place to look since the this only started with battery replacement?


Thanks!

 
Rep Power: 229

I now the 2001+ civics do a self adjusted idle reset if the battery is removed.

You basically don't touch it for 2 minutes until it locks on to a steady 750rpm idle. It needs to complete this idle hunt once then the basic settings are stored until the battery is removed again.

Not sure if the same applies for your generation.