my elantra has a manual transmission and when i am in any gear besides 1st and reverse when i give it gas the rpms go up but it just doesnt seem like im getting any power or gaining much speed what should i do?
There is a good chance your clutch is slipping. With the car stopped put the trans into 4th gear, apply some gas (rpm up to about 2,000) and let out the clutch. If the motor stalls the clutch is OK. If the motor keeps reving and the car isn’t moving much then the clutch is slipping.
Usually this means it is time for a new clutch and assorted other clutch related parts. On some cars years ago there were adjustments that could be made. Most cars today are self adjusting until the point where the clutch plate is worn out and needs to be replaced.