I have a question, does the Fuel Cansiter Purge system only work in closed loop?? My friends TPI runs GREAT in open loop. BUT, as soon as it goes into closed loop, it idles like crap....rpms "sometimes'" jump around. I know that the plugs have been replaced, and the wires have been checked. The fuel filter is unknown. The cap and rotor are about 2yrs old...but only have I think about 10K on them, but are clean of residue/buildup. There is an unusually strong smell of gas around the canister.....but usually after the car has warmed up or has been driven. The engine itself was orignally in my Z28, but has been put in his RS. Im just curious if the purge system only works in closed loop or not. I also know that the 02 sensor is brand new and was installed correctly. The IAC was cleaned and adjusted prior to having installed in his car....and worked fine. The TPS doesnt have to be adj since its a 91 correct? Please help......I dont want him to think I sold him a bad motor....thanks in advance