Okay, heres how my morning drive to work goes. I start it up. The colder it is it seems the harder it is to start. After about 30 seconds whether it is still idling or I'm already headed down the road it starts bucking really bad with light pressure on the gas. If I give it more gas it still jerks but the exhaust makes the popping noise. If I floor it it will stop jerking and popping but it is slow to accelerate. Very few times when I have floored it, it would just start bogging down real quick. After about 15 seconds of it jerking really bad it may drive right for a minute and then start jerking but not as bad. And for the rest of the 30 minute drive it may run perfect and it may lightly jerk the whole time. It will start lightly jerking at any time, any rpm, and any gear. When I'm at idle and it is in this "mode" it idles around 650 to my normal 900 rpms and it shakes the whole car. It seems like most of the time if I'm driving and the car is running fine when I go to stop and let it idle for a sec the rpms will drop and it will start lightly jerking again as I go through the gears untill who knows when. It has been doing this for 2.5 years!!! It was really bad when I got it but I replaced the TPS, EGR vacume hose and IAT sensor. I have also just replaced the cap, rotor, plugs, checked ignition module, adjusted timing, checked MAF and cleaned it, checked ECT sensor, replaced thermostat and ECT sensor for dash, replaced pcv valve, looked at all wires and vacume hoses. Checked fuel pressure and it is perfect even when the car is jerking, cleaned IAC valve and tried to adjust it but it was already at the best setting. My oxygen sensors indicate rich and lean on both sides. It can change from running perfect to running like crap at the flick of a switch. When I replaced the spark plugs #8 plug had some oil on it like it was leaking through a valve seal. All others were perfect. Please give me some ideas as to what it could be!