well you can usually hear a difference if you have an exhaust leak, but you can just visually inspect your exhaust system for rust and holes as best you can. The most likely source of that as hammer pointed out will be a broken bolt right where your exhaust bolts onto the manifold. You can check this pretty easily by scooting under the truck near the front wheels and looking up near where the wheel cover is. There is a heat shield and then you should see 4 tubes running into your manifold (on each side) with I believe 8 bolts or so bolting it into the manifold. Check for the heads of the bolts to have come off, the ones towards the back are more likely to be broken. If you search for broken manifold bolt you can find several threads and some pictures of what to look for. Hope this helps, tried to make it as straightforward as possible.

 

I too am having the p0300 code comming up and all of this information is helpful as for what to look for.

Thanks.

 

If you solve yours before I solve mine, let me know what you did! The code has gone away for me, but will show up randomly 1 day, then go away again. So I haven't done much yet. I need to figure it out though.

 

Did you ever do a compression test??

 

How many miles? maybe time for wires. boots and spring on the coil packs. If you un pluged any coils make sure they are fully seated.

 

No because I'm currently broke and the light went away. It will come back one random day, but go away again and run fine. I am going to do it soon though hopefully.

 

Is the misfire always on the same cylinder?????

 

Its Random therefor it must be atleast 2 cylinders.
Im gueesing your having a leak some where that is getting bigger.
To The OP do a compression test when you can this will tell you if you are flirting with catostrophic failure.

 

well I had mine throw a new code since I borrowed a obII reader ...P0152 bank 2 P1(pre cat o2 hi)

So Am waiting for another code to be thrown to see if there is a pattern emerging.

Has anyone ordered from Rock and had parts ship to Canada?

Want to know about brokerage fees charged or not...via fedex.

 

Good choice with Rockauto, cant say anything for Canada though. Make sure you stick with NTK,NGK