hi everyone. I'm having this weird new idle hungting problem. The car idled perfectly two days ago. I 've been having a hesitation issue at part throttle between 3k-4k rpm. So I pulled the codes yesterday, and came up with a knock sensor code. Code 34. So i switch the ecu back to mode 1 and go for a drive. I find out that the car is now hunting for the idle really bad. When it gets real bad it nose dives to zero rpm and stalls the motor. I'm thinking that maybe since the codes get wiped out when you go back to diagnostic mode 1 it also resets the computer.

So i'm thinking that maybe my ecu is trying to learn again. Only mod on the car is the 3" catback. Car is NA.

I'm thinking maybe i should give the car a week to see if it starts idling properly again. Any other possible suggestion from any of you would be appreciated. So far the car just hunts for a idle, a check engine light has not popped up. If I drive at a regular pace the car drives normal, except for the previous hesitation problem that shows up occasionally.

Any idea how long it should take the ecu to relearn ?

check out your iacv see if its dirty, real quick to do and if its the problem then it will be solved with a little bit of cleaning or maybe a new one but you can usually get away with just a cleaning

ever fixed this problem?

yeah I fixed it. It wasn't a learn time problem. I let it go on for a good week and it stayed the same. I checked/set my timing, then at the same time adjusted my idle per the FSM procedure. I guess my idle screw was just way off from its previous setting.

What I wonder though is why the car ran fine before i checked the ecu codes, then after the ecu was reset why it all of a sudden needed the idle screw adjusted.

When ever the ecu comes across a problem it will find a way to deal with the problem. At the same time if its a big problem it will also light up the cell light. So the car adjusts to the problems and when you reset the ecu all of a sudden its ways of dealing with the problem are lost and the car suddenly no longer wants to idle correctly.