A vacuum leak will cause a high idle with no corresponding increase in power.
It is common for the oil pressure warning light to turn on when engine speed is too low, but your description could suggest the oil level is low too or the sending unit is defective. Check the level first with the engine not running. If it's okay, and there's no abnormal noises from the engine, have your mechanic check the actual oil pressure with a mechanical gauge. If the pressure is normal, suspect the sending unit.
Thursday, January 15th, 2015 AT 7:46 PM