My 1996 Toyota Camry LE 4-cylinder recently started making what sounded like a hiss whenever I press the gas. The sound is clearly audible from the passenger side dashboard. It is accompanied by loss of engine power; the car does not accelerate at its normal speed. The sound occurs only when the car is in gear, not neutral/park. The car will stall if I press very lightly on the gas while it is moving slowly.

I jacked the front of the car up and placed it on jack stands so that the front wheels were off the ground. I was then able to take this video which illustrates that the sound is a clear rattle which grows into a spin as the engine speeds up. I thought the sound was coming from the EGR Vacuum Modulator, so I replaced it, and nothing changed.

Should I replace the EGR valve? Or is this something entirely different? Since my first attempt to diagnose the issue failed, I'd rather get more advice before I buy more parts.

  • A hiss and stalling could be a vacuum leak, that's where I'd start. You can use a length of tube as a stethoscope to find the source of the sound.
    – GdD
    Commented Mar 23, 2021 at 9:06
  • @GdD brilliant stethoscope idea, I'll try that this afternoon.
    – MD XF
    Commented Mar 23, 2021 at 14:39
  • It works great and costs nothing, just make damn sure you don't stick your hand into anything spinning!
    – GdD
    Commented Mar 23, 2021 at 14:42
  • @GdD I actually bought a mechanic's stethoscope and still couldn't find the source of the rattling, however I noticed that the hose connecting my EGR valve to modulator had blown off entirely. Replacing it silenced the hissing and solved all driving problems for about 1 minute; it blew off again. I installed a thicker hose and it did not blow off, however after driving 5-10 minutes the rattling becomes slightly audible again and the acceleration becomes choppy.
    – MD XF
    Commented Mar 24, 2021 at 1:12


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