Hey all. My 98GT is giving a P0455 or P0452 engine code. It's an Evap system leak, either large or small. It comes and goes as it pleases. Ive been fighting with it for about two months now. Sometimes when I clear it, it will go weeks or more before coming back, other times, I'll clear it and it'll return in a day or two. I've been over the fuel, exhaust, vacuum systems on the car so many times I'm cross-eyed and I cannot find anything the would suggest a leak anywhere in the system. Car runs great, and it recently passed smog with flying colors, but the code is annoying. Anyone have any other ideas on what I need to check? Thanks for the help as usual! Oh and the code came up long before I started modding the car. Thanks abunch!

 

I don't know if I can help much but here goes... If you are certain that all the lines and everything are good and not leaking, I would look towards a sensor. That is one system on this car I don't really have any experience with and all documentation I have for it is rather confusing. I'm pretty sure you can find documentation on how to properly check the sensors but I don't know off the top of my head. Also, If you're handy with a multimeter I would check the wiring to rule that out. I had an O2 sensor wire with an intermittent short the gave me hell for months. Hope this helps,

Steve

 

Yeah I'm thinking I'll have to spend a few hours hunting for anything that can cause that code to pop up. Just have to keep searching. Thanks for the info! =)