GROC80

So when I got all new tires mounted on the car a few weeks ago I went to a name alignment place & got the Lifetime alignment special. Apparently to conduct the service they had to disconnect the battery to disengage traction control settings & allow for the alignment to be done. When I received the car I went to start it and the car made a really ugly vibration like the idle was trying to stay steady but would struggle. I upgraded to 17" tires at oem recommendations & the mpgs went down also. Why would I have these little vibrations every now & then now, they aren't frequent but annoying? Also would the 17" tires cause a loss in mpgs? Only other thing on the car is a K & N drop in filter but when I added it the first time the mpgs went up drastically. I just heard stories that the oil in the filter can cause issues, just wanted some input. Thanks!

gs_aristo

Sounds like a Firestone.. Never had to ever disconnect a battery to do an alignment. As far as 17s go mpg will go down unless you go with a lightweight wheel since you have oe specs.

K&N filters are fine.. just don't put them in dripping wet.

The only vibrations I can come up is with your ecu trying to re-learn the maps when whoever disconnected your battery. It could also mean your TB may have some build up since you had an intake on it previously.

GROC80

^^^Thanks is there something I can try to remedy the problem? It vibrates every now & then and I thought the same thing as far as ecu. Would disconnecting the battery & let it reset do more harm than good? That was my initial thought. Thanks for the wheel advice too, weird maybe they alloys weigh more with the tires mounted because they felt lighter than the oe wheels. As far as the tb I can ck that too just didn't see that being a major factor, running stock intake with the drop in. Thank you for the feedback.

Metalcoffin

What year is your xB? There was a recall on the 2008 I know for sure(possibly other years) about the coil packs. Every now and then the engine stumbles, usually when it's hot and when you come to a stop it'll almost die or die every so often. Toyota says it's a problem with the coils overheating and you can take them to the dealer to get them replaced. I still yet to take mine in and get them replaced but it happens very seldom and gas milage is A ok.

Giantdefy

Mine did the exact thing after leaving the battey unplugged for an hour. What happens is, the ecu gets reset and you need to re-teach the ECU. Once the ecu has reset, driving it immediately on a cold motor will cause the ecu to idle very low (below 500) and you get the engine shake like it wants to stall.

-The fix is, unplug battery for over 30 minutes.
- plug battery and start car and let idle until it warms up
- after the warm up, drive it
The idle should now be over the 500 rpm mark (around 750ish).

GROC80

I will try the battery unplug & if not look into the coil pack. Was not aware of the recall. We have a 2011.

criminaltc

No need to worry, it is only because you unhooked your battery. All scions do this. It's the ECU as everyone else already mentioned. It'll learn how to drive again.