All of a sudden I had misfire codes on my 2004. Read up on it here and changed the plugs and wires. Kingsborne wires and Bosch plugs. After starting it ran fine with no codes after driving about 25 miles. Today started it up and it ran rough with the flashing check engine light and the p0302 code. Turned it off ;et it sit of an hour and just to check again started it. This time the p0302 repeated twice, along with p0303 and p1300.

I will check the plugs and wires again but it would seem that if they were not right I would have gotten the codes right away and not the next day.

So what else before I try a coil pack change? Doubt it's the coil- seems like it would have thrown the codes right away. As maybe a coincidence and maybe not- I have not heard the SAI run recently. Usually it does at startup for a short time. Anything else I can check right off?

Has a newer CPS, heads done about 40,000 ago, always use 93 octane, has newer fron o2 sensors, newer MAF. Really frustrating. The wire job was rough for me, I hate to do it all over agin. Made triple sure everything was seated well and although I couldn't get a great look the coil pack were not obviously corroded.

Anything easy to try first?

 

You must have accidentally pulled the coil pack harness connector and got loose in the process. The truck will run even one coil is unplugged but immediately the ses light will turn om and misfite codes will showup.

 

Thanks for the reply. Do not understand though. Where is the coil harness? Nothing pulled out except each plug wire on the coils. How would that explain it running fine with no codes for 25 miles? I am missing something in your explaination.

 

Im just thinking that in the process something might have gotten loose. Since you have driven good 25 miles. I know its difficult to get in there but you just have to recheck the connections. But depending on the milage, the coil should have been replaced as well. I just did the entire replacement and had issues after with misfires. But at the end i replaced the injectors and now no codes at all.

 

I see what you are saying now. If I have to take it all apart again to look I will get the coil packs and do them, it cannot be that much harder that the wires- I hope.

164,000 miles.