hi,i just changed the pcv system on my volvo 850 estate,i replaced the whole thing,and also cleaned the throttle body,and took the fuel rail off and cleaned the injectors.when i restarted the engine,the idle was really rough,and i had black smoke coming from the exhaust.i was surprised, as before i did the work, the car has been a perfect runner.my first thougt was i had'nt put everything back together correctly.the only doubt i had was this,thevacuum hose from the fuel pressure regulator, and the hose on the top of the flame trap,that fit to the nipple on top of the throttle body.i put the regulator hose on the upper connector, and the flame trap on the lower one.so i swapped them over,also somebody told me that as i had the battey disconnected for more than five hours, i should leave the ignition switched on for 5 minutes before starting up.so, i did this, and the engine ran perfectly.only thing now is ,i have a warning light on the dash,its a triangle just below the parking brake light,that's telling me there's a fault in my fuel or ignition system,this light has never come on before,but is now on permanently.does anyone out there know what's going on?