Hi forum, Its been a while since ive posted, I need help with my cat once again. On cold starts and warm my cat hesitates the engine struggles to build up rpms and on red lights the rpm also drops time to time. Also herd a noise last night when i went over 60 km/h sounded like a fan being hit with a playing card. I checked the fan and the engine bay everything seems to be in order. I have been using mid grade fuel with octane boosts and fuel injector cleaners every 5000k oil change. I cant seem to put my finger on it, I thought it was the alternator at first but could be wrong is there any way of diagnosing this problem?

 

Hey Jessy.

Getting a check engine light at all? Sounds like a possible vac leak, can you hear any hissing type noise when idling? Start the car, open the hood and have a listen. Not sure about the fan/playing card noise, that's a new one. Is the noise all the time at or above that speed or did you just hear it once? Does it speed up with the speed of the engine? Give us all the details you can and let's get this figured out.

 

Matter of fact YES!!! Yes i do hear a hissing noise ive been hearing this "hissing" since last summer...i thought it was the ac compressor or something, it hisses after i shut her off aswell... would that explain my red light incidents? ...Whats the next step can i do the fix at home or got to take her into a mechanic?
Thanks for the quick reply Chris X

 

oh and no engine check light or any lights at all

 

find the hiss. if you can hear it from your driver's seat, you should be able to isolate it from the engine compartment. Look at vacuum line joints, hard plastic pieces, pieces exposed to heat, etc.

 

I cant hear it from inside from the cabin itself i can only hear it time to time when i pop my hood with the engine turned off after driving around, which one of the hoses is the vacum hose? is it as easy as losening the metal clips at each and and popen in a new hose?

 

Strange, you should be able to hear it with the engine running while you have the hood open. Can you try this and let us know if you can hear it? Obviously if this works then you'll be able to locate which hose/line is leaking. Common suspects are the pcv hose that runs alongside the intake and the hard plastic line that runs to the brake booster and has a check valve that sometimes leaks.

And typically you get a check engine light when this happens. We might be off base here, but if you could check for the hissing noise with the engine running then we can at least eliminate that as a variable if it is something else.

 

The good news....hissing went away
The Bad...on cold starts the engine is still hesitant and struggles to build up rpms; along with that a stench of exhaust and fuel comes from the engine, also a big puff of white smoke came out of the rear. Once warmed up ( about 5 minits) i drove her to school with no problems, shes smoother than ever better than new (thats what scares me) i went up a huge hull no problems, however i know when i go back to her after my exam she'll be struggling to start up. Ill try to post a youtube link of a video, um ready to just get this one last thing fixed and send her on her way to a set of new hands, cant afford any more mishaps, tuition already is up the rear!