Hello, I was wondering if I can get some help or suggestions. I have a 99 maxima SE 5 speed that is in great shape, but just last week there is a hissing noise when I press the gas pedal hard. when my car is idling there is no problem either. If i drive really smoothly and slow, you dont here nothing. You can hear the hissing noise more on the highway especially when I am trying to accelerate at a faster rate. I do have an aftermarket cold air intake, but I have had it on for over a year and never had any problem, so i doubt that is the problem. From research, I think it might be a vacuum leak or exhaust leak, but Im not sure how I can find out what type of leak it is. I was planning on spraying carb cleaner or wd-40 to see if I have a vacuum leak. Has this happened to anyone recently?? Does it sound like a vacuum leak or can it be something else.? What should i be looking for? I just had maintenance done on my max and I am on a tight budget now. Any help or ideas is appreciated. Thanks!!

 

I think this is a good start...spray it on all hoses and listen for any fluctuation on idle. If it fluctuates in any area, there could be your leak there. Also, rev the engine manually at the throttle body then listen and look for the hissing noise. Hope that helps...

 

Thanks, I am gonna check first thing in the morning. Btw, is it safe to use WD-40 to check for vacuum leaks, or should i use carb cleaner instead?? Thanks

 

Carb cleaner for sure. Just not sure about wd40, although cant imagine it causing any harm..

 

So I couldn't find any vacuum leak, IDK if i missed it or what.. When i rev the engine however, it sounds like the noise is coming from under the car?? I'm not really sure what to do now?

 

Exhaust leak?

 

idk but on another (non maxima) car that i had years ago, a clogged cat was making the exhaust make a weird hissing sound upon acceleration.

 

+1 next possiblity

I'd put the car up on lifts and inspect under there while someone revs the car for you. Process of elimination...

 

Check the flex section on your y-pipe.

 

Thanks for all the advice, i will check under the car tomorrow and let you guys know whats going on. btw what would be the easiest way to check for an exhaust leak under the car? that may sound like a dumb question, but I'm pretty new to all this.

 

 

WD40 is DE*greaser. idk why alot of backyard mechanics think its lube. if that goes in your engine, your ****ed. it separates oil. don't use it anywhere near the vac lines/intake.

 

SO I have found the problem! it turned out to be an exhaust leak by the back rear tire. I felt the air coming out even without revving, but now how do I go about fixing it? I don't have any idea how to fix that, so I was thinking about taking the car to a mechanic,.. how much is it usually to fix an exhaust leak?? btw is there any temporary fixes that I can do right now?