i know from experience the p0440 is 99% of the time the purge valve. i'm aware of the hyndai trick, but i always stick with oem stuff. when it happened to me, i changed it and the thermostat and my gas mileage almost doubled. now, under 10,000 miles ago, i had the heads rebuilt, new plugs, etc. not long ago, i started getting random misfires on 2 cylinders that went away after engine warmed up. I thought i was doing my engine a solid favor by using long life coolant (red stuff, dex cool and the like). a month ago, my lower hose assembly sprouted a leak, so i replaced the whole assembly down there, and after reading from another post about not using red coolant, i flushed the crap out of the system and changed back to good ole green coolant. my 2000 disco has never been happier and no longer misfires or acts up when the weather temp goes from 70 to 20 degrees anymore. which i'm sure you're experiencing. just my 2 cents. if you are using the red, get it out. NAPA now sells pentosin products and has green coolant with the organic anti-corrosion technology in it and that's the stuff LR says to use. Also, make sure no vacuum leaks or un metered air is being sucked in, causing lean or rich conditions where misfires can occur. good luck.