Replaced spark plugs, shifting changed

[FlatlanderIA]

All, right after I replaced my spark plugs with new NGK plugs on my 2000, I noticed a change in the automatic shifting. To me, it seems like it shifts from 1st to 2nd and also 2nd to 3rd at a slightly higher RPM. Is this possible/normal? I know I'm not imagining it... I was wondering if anyone else has noticed this before. Thanks....

 

[jpontius]

Did you disconnect the battery during the installation of the plugs? If so, it takes the ECU a while to re-map and normalize to new conditions after being reset.

Even if you didn't reset the ECU, it's possible that an improvement in fuel combustion will take some time to be adjusted to.