Mkiii

[Zprodo]

I have an mkiii that seems to have an endless supply of problems...So I have some questions i was wondering if someone could help me answer.

First when I rev the engine it sounds like there is water splashing around in my engine compartment. There is no water in my oil pan so I'm thinking its not a blown head gasket. If anyone could help with that, thank you.
Also my idle is at 1500 rpms. Is that normal for Supras? I'm thinking its kinda high. Does anyone know what the problem is or how to fix it?
My oil pressure gauge doesnt work either. I bought a new sensor and that didn't fix the problem, i checked the lines going to the sensor and they were all good and getting electricity. Is it my gauge that is broken? If so how expensive are new gauges?
Finally I love this car its very very fun to drive.