Sucking Noise????

[Trans am Man]

Ive noticed a sucking noise coming from the top of the engine lately,i cant seem to pinpoint it,but its loudest around the throttle cable area,the car seems to be running fine,but surely this noise isnt normal?

Any help or advice on what to look for would be great.Its a 96 lt1

[Christopherrr]

What are your mods of any? Check leaks in your EGR area....tubes, connections. How is your car running?

[Trans am Man]

The cars standard,its running fine,although maybe slightly down on power,although ive only ever driven this one so ive got nothing to compare it with,as they are rare in the UK.But its not as quick as my 86tpi corvette,and i thought id would be.

[Christopherrr]

if you're down on power check your cats...a clogged catalytic converter will simulate a 'sucking' sound, like the one you'd hear from an air box. see if your headers glow...

[Joe 1320]

Ive noticed a sucking noise coming from the top of the engine lately,i cant seem to pinpoint it,but its loudest around the throttle cable area,the car seems to be running fine,but surely this noise isnt normal?

Any help or advice on what to look for would be great.Its a 96 lt1

The first step would be to check for any leaks in the air intake system. That system consists of all the intake ducting from the filter to the throttle body as well as all the vacuum lines. First visually inspect all the lines for cracks or plits, if check all the rubber couplers and elbos to see if they are torn. If you can't see anything, try using throttle body cleaner. While the engine is running, spray the vacuum hose fittings and intake joints one by one to see if any outside air (and flammable cleaner) is being drawn into the engine. If it is, every time you spray there will be an effect on the idle. Starting fluid could be used too. Just remember.... the stuff is highly flammable so don't go goofy with it and spray down hot exhaust manifolds or do this while smoking.

You could also check the emission hoses' fittings and connections to see if anything there is causing the hiss.

[Trans am Man]

So,just to clarify,there shouldent be any sucking noises?

[Injuneer]

So,just to clarify,there shouldent be any sucking noises?

Not unless your air intake looks like this - 'cause this one sucks:



Seriously, check the 90-degree elbow that connects the MAF sensor to the throttle body. As Joe points out, it can get torn. Or, the bottom edge can fold over when you try and slip it over the bottom of throttle body, and leaves a large gap for air to leak in, bypassing the MAF sensor, and screwing up the PCM's attempt to provide the correct A/F ratio.

[marlon95]

i have been driving around with a sucking noise for months, and always thought the sucking noise is normal. it's not. when i finally just by accident found the source of the sucking noise, and corrected it, the motor runs now like a sewing machine. my sucking noise came from a big hole in the rubber hose going to the pcv valve. never noticed it, found it just by accident. but i think if i had have just taken my time and inspected all those rubber hoses, i would have found it months earlier. located on the Driver side