I have a 87 N/A hard top. It has 64k original miles. She just became my DD and i started to notice a hissing noise coming from the intake manifold. Has anyone ever came across this? I'm not sure what it is but I think it has to do with the throttle body. I also noticed that I haven't been getting a good mpg. Maybe this hissing sound is causing it?
Hissing Sound from the Intake Manifold
- Thread starter pnoixballa
- Start date
You have a vacuum leak. Find it, fix it, and enjoy a hiss free, good mileage commute. 
To help locate the leak, you can do a few things. 1) pressurize the intake and listen for leaks, 2) start the car and listen that way, but it's difficult with the engine running, 3) use carb. cleaner and lightly spray around hoses, joints of the manifolds, etc... and listen for the idle to raise, or that same method with propane gas. If the idle raises when you spray somewhere, you've found your leak.
To help locate the leak, you can do a few things. 1) pressurize the intake and listen for leaks, 2) start the car and listen that way, but it's difficult with the engine running, 3) use carb. cleaner and lightly spray around hoses, joints of the manifolds, etc... and listen for the idle to raise, or that same method with propane gas. If the idle raises when you spray somewhere, you've found your leak.
shaeff;1136309 said:You have a vacuum leak. Find it, fix it, and enjoy a hiss free, good mileage commute.
To help locate the leak, you can do a few things. 1) pressurize the intake and listen for leaks, 2) start the car and listen that way, but it's difficult with the engine running, 3) use carb. cleaner and lightly spray around hoses, joints of the manifolds, etc... and listen for the idle to raise, or that same method with propane gas. If the idle raises when you spray somewhere, you've found your leak.
With a vacuum leak on my 7M-GTE, if I stayed out of boost I got a consistant 16.5 afr while cruising. (My MPG increased.)
shaeff;1136309 said:You have a vacuum leak. Find it, fix it, and enjoy a hiss free, good mileage commute.
To help locate the leak, you can do a few things. 1) pressurize the intake and listen for leaks, 2) start the car and listen that way, but it's difficult with the engine running, 3) use carb. cleaner and lightly spray around hoses, joints of the manifolds, etc... and listen for the idle to raise, or that same method with propane gas. If the idle raises when you spray somewhere, you've found your leak.
I already tried spraying the hoses but I didn't find anything. Also I tried squeezing the hoses and still couldn't find any leaks. Any other ideas?
Is this what's causing it to burn a lot of gas?
i had a hissing noise on my 01 camry and i belive if i read right you just bought the car??? correct? if so check to see if a do ti yourself mechanic forgot to put a gasket on the EGR valve. That was my problem. But also check for vacum leaks just double check. Im just tossing in some of my problems ive had in the future. So dont everyone get on me lol. Just trying to toss in a idea
