Thought I would tap the FWD brain trust. We own a 97 855 NA, had it since new. About six months after installing a new engine I started having CEL/EVAP problems. I get the 0455 "small leak" code. I have been through the evap system front to back several times. Have fixed several minor leaks in hoses, changed others that don't seem bad, changed the little purge valve on the fan shroud, changed vacuum elbows, changed fuel caps back and forth (currently has a new one), replaced the J hose atop the tank at the beginning, pulled the fender liner and checked the solenoid valve and all that plumbing. The fuel pump was out at one point and I found a small crack in the top as well as a top tank seal that may have been bad--no go. I have vacuum and pressure checked the system from a half dozen points without finding a thing. Fill tube has a slight bit of dinging from the fill nozzle, but nothing even close to serious. At my wits end after a year of diddling. The only thing that I can point to is the fact that the CEL may light in a few days, or a few weeks. However, if I clear it, and leave the car idling, it will set after a few minutes. I am tempted to check the tank sensor and a friend recommends doing that at the ECU plug, but haven't pulled out the schematics to find which pins yet. Anyone have a similar experience? My daughter's S70 has a similar problem, but will take 3-6 months to set the code! Same work has been done. Both have new PCV plumbing. Thanks, Dave