So I went to clean the corrosion off of my positive terminal today. Which I still haven't figured out why it is so corroded. Anyways; I clean everything with a wire brush/baking soda etc. In the process I break the bolt that holds the terminal on the post. So i go get a new bolt & hook it up in the parking lot. I had some battery terminal protectant that i sprayed on as well. Go to start it up and I noticed right way it was sluggish/idled odd it was rough. I took the posts back off made sure everything was ok etc. Then i noticed the VSC TRAC WARNING lights on. So i went to have the battery & alternator tested. They are 100% fine. I did nothing else to my car...what would cause this to happen out of the blue? 2005 scion xB. Everything was running smooth until i cleaned the corrosion off.


I've been reading about this problem, but no none seems to have the rough Idle I have...I do have a fujita f5 cold air intake aswell..going to advanced auto to get the obd read tonight...

 

After disconnecting the battery the car has to relearn some things and will idle funny for a few minutes just let is sit for a while and take it out for an easy drive. If it feels like it may stall while stopped just give it a little gas to bring up the rpm's

 

how long would it take to "straighten" up per say?

 

Takes about two "drive cycles" which are essentially cold start, some idle time, some start-stop-shift city driving and at least some sustained high speed cruise - as on a highway. A couple of complete cycles like that (maybe a half hour's driving), driving as you normally would, should get your patterns learned.

 

or it could be p0172 (Fuel System Too Rich "Bank 1") at least that's what the diagnostic says...Apparently some of the corrosion from the terminal that i was cleaning must have gotten to a sensor somehow? Is it possible that the sensor hasn't failed and just needs cleaned? The sensor O'reilly auto parts quoted me for is $150...any ideas where the HO2S sensor(s) are?

 

Your Scion's black box actually could be running the engine a bit rich until it learns the specifics of your exact engine by being driven.

Whenever power is removed it resets itself back to the original factory settings until it re-learns what it needs to modify for your particular engine and driving style.

You may just have a unit that was reset and will re-learn, or you may have a problem that needs looking at.

If it were mine (it's not) I would give it a chance to learn, and if it doesn't, THEN I'd take a look at the sensors in the exhaust...