Will I have to do jail time for a failure to appear?

An arrest warrant (usually a bench warrant for traffic matters) means that you can technically be arrested at anytime and anywhere. Given the age of the case, I would go the court where the warrant was issued and attempt to either get a new court date to appear or see if you can be arraigned on the warrant and given a new court date. You should not lose your job, but if you get arrested the police can hold you in custody for a few days before you see a judge.