Recently replaced 3 fuel injectors in my car, put it bak togather, she runs great, now a few weeks later I get this high idle in park (between 1000 and 1200 rps) I tried listening for it, but i cant really tell where its coming from. I hear it near the firewall side of the engine, I know it not the brake booster or fuel pr hose or none of the coolant lines on the plenum, so Im pretty much stumped on this one.

 

Check coolant temp sensor is plugged in. Also check operation of IACV.

 

 

+1^^ Or use carb/choke cleaner. Spray it on the potential leaking places and when it sucks some of it in it will makes the rpm increase. You probably also have vacuum lines running to your charcol canister which would be in the top left hand corner of the engine bay by the firewall.

 

My money is on the tiny little vacuum lines running back to the heater valve. Those are prone to dry and crack as well as easily slipping off. I've owned this car for years and every few years I've had to either replace these lines or re-install them becuase they come loose. Even with the small lines, the noise can be very audible.
But, you definately need to spray something in there to make sure there are no other leaks.

 

I will try to see if I can pinpoint it in the morning. So I just get some carb spray/ or starting fluid? WOuld WD-40 work? I have a can of that in the car. I will keep you updated on the results.

 

well I found out where the vacuum leak was coming from, I though it was coming from the fuel injector itself. All the hoses on that side of the engine were recently replaced, and didnt seem to leak. But I took a good look at the fuel injector in question that the hissing was coming from, after I sprayed water on top of it with the car running, and lo and behold, it was the fuel rail insulator rubber part that was not seated correctly, which allowed the injector to not sit into the hole correctly. That explains the loud hissing noise and the stumble on acceleration, and the high idle. I will take her apart tomarro morning and correct this.