Car is idling high. Speedo stopped working and service engine soon light is on.

Those issues are all BIG issues; none are "little". It is likely that they are all separate concerns also. The check engine light is most likely related to the engine idling high. The high idle could be idle air valve related, or a vacuum / air intake leak. ' For the speedometer issue -- the speedometer is driven by a cable. Either the cable has failed, the speedometer head has failed, or the driven gear that drives the cable is faulty. The air bag light is flashing out a "code" for troubleshooting. Count the flashes, then wait for the short pause, then the second set of flashes -- that's your 2 digit code. If you get it, report back here, and we'll see if we can look it up.