I keep getting codes P0455, 422. Large and small evap leaks. Checked hoses/lines going to tank. Looks good. Sometimes I’ll hear a leaking noise for under the hood. No doubt it’s that, but I don’t hear all the time. Almost sounds like when you turn off a/c but longer duration. This morning to work, it stayed on most the way. If I let off gas, it would die down, when gave gas, it would rev back up. When I could stop, it had quit. Any ideas??

 

See if a shop around you has a smoke tester. Either that, or build one yourself. There are vids on youtube of how to do so.

 

The DIY smoke testers and the cheap Amazon ones use mineral oil for the smoke. The smoke tends to condensate pretty quickly and only travels maybe 2-3 feet before disappearing. Something to keep in mind especially with the long EVAP lines.

If you can hear it hissing you might be able to pinpoint it with a "listening device" which for me is a piece of hose held to my ear and the other end as "detector". At first glance I'd think it's something with the leak detection pump, if it sticks open it acts like a giant vacuum leak which would explain the stumbling.

 

Take a can of brake clean and start spraying around intake, hoses etc when she revs up you found your leak, unless your plenum is bad in that case have a peak down the throttle body

 

Thanks! Good idea. I’ll try it.

 

Look a the vac port (front of the throttle body left side looking at it from the front) it comes out and goes into the solenoid then back to the evap stuff.