P0303

Got code p0303 on my 2002 vw jetta 2.0L. Ive replaced coil pack and plugs and wires also oil and fuel filters. Sitll no luck. It does it no matter what the weather like and sometimes it doesnt act up but the check engine light is on and even sometimes the light will go off completely and it will work fine. Sometimes ill start to drive and a few minutes later then it starts to act up. And other times it acts up as soon as I start the car. Usually when it finall;y warms up all the way (because it seems to have a problem doing that too) I can turn off the car and restart it and it will stop acting up but the light will still be on. Note: it only blinks when it acts up other wise its steady on not on. Note: If the light goes out its only out for maybe a day. Any help?