Hi All,

I just recently purchased a 2001 Mazda Millenia 2.5L (beautiful car). Upon driving itI noticedit ran rather rough as in it was"missing". Open the hood "whala" still had the OEM spark plugs, wires, distributor cap and rotor at 105K.After changingthe spark plugs, wires, distributor and rotor, as well as dumped some Lucas FuelTreatment into the tankon a couple different occasionsfor preventative sake.It ran much better than before (after changing of aboveparts) but it seemed to still "miss"or run rough but ever so slightly, to the point it wasdifficult to isolate. It would slightly jerk on take off not that "jerking take off" that seems to be common with these cars as I've read but different. I tried to reproduce the "jerk" on take off buthave not been able to. Whilesitting at idle it runs smooth over all, the RPM needle doesn'tmove at all but you can still feel the roughness and slight "missing" indicating there's a problem.This has gradually gotten worse as my MOTHER got in the car and said its such a beautiful car but its "missing". So I pulled up the firing order for my car on the internetand made certain I put the wires back on correctly...no problem there! I then reseated all the wires in case there wasn't a good connection. After doing that the ce light came on (ce light hadn't been on prior to this)...I zoomed up to the local auto zone and had them check the code...P0300!Random cyclinder misfiring! Well...whata you know! (Glad to see it's staying on topof things). Onmy way back home my carshut off on me while I was sitting at a traffic light...its NEVER done this while I've owned it!I considered takingout the spark plugs and checking whether they are allgapped properly as the counter person who sold them to me said they were pre-gapped for my engine already. Also, I thought maybe itcould be the fuel injector(s) or a pesky vacuum leak but listened and checked for that...nothing! I know how to do basic tomoderate maintance and repairs so I'm hoping I can do this myself...