Car question help part 2?

Question

hi i have a ford mondeo 1.8 16v 1993 dohc my car sounds like it is reving on its own when idle just slightly i have checked air filter and had alook at sesors and all look ok i can here a hissing sound by the right part of engine just below maf sensor and ideas thanks

Answer 1

sounds like a air leak. a rubber hose maybe cracked or come of a port  and that would be map or mat sensor one is atmos temp other is pressure any air leak around manifolds give higher idle  as op to lpg it makes them lower there idle speed quick way to check hold a peiceof tube say about 1/4" to your ear and move other end around suspect area you should find problem if you cant find it maybe manifold gasket see if bolt are tight have seen chunks fallen out to

Answer 2

Check for vacuum leak

Answer 3

a hissing sound, you say?. get some carb. cleaner of starting fluid and spray around where you hear the hissing, sounds like a vacuum leak.

Answer 4

i would make sure the intake is not leaking and that all vacum lines are in place