ShellinaH

Hello!

So I have a 1999 ES300 that gave up on me last night. It lost significant power going up a hill and started making hissing sounds like air escaping. When I pulled over and turned on the heater, fumes started coming in the heating vents so strong they made my eyes sting and gave me a headache (more than the car already was!).

It had been misfiring for a little while so this morning I sluggishly drove it to an autozone and had the codes read. The man told me it was either my plugs or my coils. I told him I had already changed the plugs so I bought a set of coils and installed them myself. That solved the misfiring issue the car is no longer shaking.

HOWEVER - the car is still making a hissing sound like air escaping somewhere and a low revving sound when I accelerate.

Does anyone have any ideas? To be honest, this is my first car and I have NO idea what this is and don't want to spend a million dollars at the mechanic so I'm trying to get an idea for what this might be.

tomf

Is the CEL on. If so what are the codes? Hissing could be a vacuum leak. Are you leaking any fluids? Maybe there is a hole in the cooling system. Can you pinpoint where the hiss is coming from?

ShellinaH

It was on. The codes all had to do with my cylinders misfiring. When I changed out the coils the light turned off.

So far I have not been leaking anything. I checked the last few places I was parked and nothing that I've seen.

I took a chance and took it on the freeway and here's what I found out - if I floor it, the car jumps to 3.5 RPMs, where usually I can only go 2. When that happens though the hissing gets louder and sputters like short bursts of hiss over and over. It also makes a low in pitch but loud revving noise. Even with that happening I couldn't go any faster than 55mph going even slightly uphill. Downhill no problems obviously.

ShellinaH

UPDATE:
so. uh. After driving it a bit I parked and turned it off. Waited a while and then started it back up again. Something right in front of the drivers spot is smoking.
I'm trying to find a diagram to figure it out but isn't the catalytic converter there? And doesn't that get damaged when your car misfires?

tomf

Do you get the hissing sound when the car is in park and idling? Do you only hear it when the car is moving? Does the hissing change when you press on the brakes? Does the hissing sound change when you turn? From where do you think the sound is coming?

Could the hiss be better described as a roar or hum?

The catalytic converter is under the car.

HappyLexus

Shellina,Exactly where is the hissing noise coming from? Does it increase when you rev the car? Is there any other issues with the car? Loss of coolant?

verbatim

My 2002 es300 is loosing power and making a hissing noise when i press the gas for over a week. Today I saw white smoke coming from the engine manifold [near the radiator.] The smoke seems to have stopped when I replaced the power steering fluid that leaked all of the way out. I just found out about this issue today. Did you ever resolve the issues with your vehicle?