Camry had an aftermarket gas cap, and I noticed when I filled up the tank, it no longer mad the hissing noise it once did, then came the engine codes (P0440, P0441, and P0446 if I remember correctly).

Anyway, ordered a factory gas cap, installed it, cleared the codes via code reader. Haven't had a chance to refill the car yet, but I've been getting my reader hooked up every evening to see if any codes come back. This evening, it seems P0440 is pending. No sign of P0441 or P0446... yet.

Any advice is well welcomed at this point.

 

P0440 means the fuel tank pressure is the same as the outside air pressure after 20 minutes. There is an air leak in the fuel tank/vacuum/emissions system.

If the other codes appear the problem area widens.

Check for:
Cap air leakage
Vacuum hoses air leaks (emissions system)
Air leak in fuel tank filler pipe typically from being rusted through
Cracks in vapor canister
Vapor pressure sensor bad

 

So, I've done a smoke test, and the EGR Vacuum Solenoid appears to be leaking smoke through the center of the unit. I would assume that isn't supposed to happen?

 

You applied smoke where to the car, gas tank?

EGR is separate from EVAP system.

 

I took some video:

 

The VSV for the EGR does vent to outside air when the EGR system is off.

Still, the EGR and EVAP (which is the cause of the codes) are different system. The test for EGR function is to apply vacuum as vacuum is what powers the EGR valve.

 

I have a hand vacuum. Any instructions I can follow to do a test?

 

Remove the vacuum hose from the VSV that goes to the EGR system. Apply vacuum to turn on EGR system and engine should stumble or quit..

 

So to be clear. Start the engine first, then perform the test? Or apply vacuum then start the engine?

 

Start engine first.