Truck runs rough once warmed up.

Im getting a p0300, 301,303 304, 305. The truck runs fine in the morning when everything is cold and not warmed up. Then after 5 or 10 mins of driving it starts to idle very rough and sputter. My check engine light blinks too. Ive already swapped the coils around to see if the code follows and all of that. Does anyone have any idea why a truck will run fine at first and then once warmed up it will run rough? Im really worried since its not the ignition coils causing the misfires

 

When's the last time spark plugs, injectors have been changed?

 

If the valves are getting tight that can happen. They lengthen when they heat up and if they aren't sealing it's most prominent at idle.

Another possibility is an exhaust leak drawing in outside air and throwing off an A/F sensor, making it add too much fuel because the extra o2 will falsely tell the computer that it's running lean. That kind of leak is usually noisy though.

 

@TokerJoker 5 thousand miles ago

 

@endagon i do have the notoripus header leak

 

I had the exact opposite thing happen to me, turned out to be a bad coil pack. Did you pull your plugs and see how they look? Possible vacuum leak? Good luck and hope it's not too serious of a problem.

 

Those are various cylinder misfires, so many that I would not expect it to be coil packs/plugs. I would look for vacuum leaks or maybe O2 sensors that are leaning it out too much when hot.

 

Well guys, it looks like i used to much anti seize on my spark plugs, so thats what is causing it to misfire. Lol.

 

Dude bro. We’ve commented here about how most plugs (especially quality ones like NGK) already have/come with an anti-seize coating. No need to add it as it causes flares/hot spots on/around the plug.

I never knew this until I became an internet expert.

 

@Professional Hand Model well now i know!

 

@Professional Hand Model ay I'm just a dumb 20 year old hahaha

 

How much anti-seize did you put on the plugs?

 

@tvpierce not a shit ton but more than recommended without a doubt

 

another thing to know is a blinking CEL is the ECU begging you to let off the throttle. Way too much unburned fuel is making it to the cats, too much of that causes damage to those expensive items.....

 

How did you arrive at that diagnosis? Unless you packed the electrode area full of anti-seize, I don't understand how it could possibly cause a misfire.

 

Internet spark plug expert chiming in here. (Better than a viral expert).

Anti seize heats up hotter than the plug spark, thus sets off the ignition pre-spark before the spark plug is timed to ignite.

Picture a hot molten goo around the threads (not timed to spark, but always hot enough to ignite fuel).

 

Could be. I had to Google "anti-seize cause misfire". I'd never heard of this before... it seems neither had the original tech in the video. The engineer offers a really good explanation of what happened. (Play it at double speed... it's long.)
I learned something new today. I'm exhausted... I'm taking the rest of the day off!

 

@tvpierce I understand your speculation. The mechanic said thats what it was, he cleaned the plugs and now my truck runs good again, so i am certain thats what it was, at least 99 percent certain

 

@Pucks18 I was skeptical until I saw the video I posted above. The anti-seize isn't directly causing the misfire. Over time it leads to fouling that in turn leads to the misfire. Good catch on the part of your mechanic.

 

This guy has good philosophy.

 

Well fuck! Its starting to slowly run rough again! Better clean the plugs again or i might just replace them all as there may be residual anti seize still

 

I know that when plugs are worn it causes excessive wear on the coils. I wonder if the opposite is true. Meaning, I wonder if your ignition coils need to be replaced. Are they original?

edit- Just read your original post where you seem to think they are fine..

 

My coils are fine. Truck was running like crap cause of me using anti seize on plugs.. my mechanic cleaned them and for a month it ran great now its getting rough again, gonna just replace the plugs with ngk v power part #7990 plugs then call it a day.

 

Jesus christ never use anti seize ever. I put my new plugs in and took one out right away and the brand new plugs already got a bunch of left over anti seize on them. Its all pooled up on the bottom of the spark plug tubes right before the threads start. Dont know how the hell I'm gonna clean that shit up. The truck def is running slightly rough at times and i know its from the anti seize. I might just take a shop towel and roll it up and stick it in there. But i will be risking knocking anti seize into the combustion chamber

 

If you’ve never done it or have no records of it being done, I would suggest taking VC’s off and doing a good cleaning and replacement of parts of VC’s with OEM.

https://www.tundras.com/threads/intake-manifold-and-valve-cover-gaskets.37347/

 

Why? I have 0 vc seepage whatsoever

 

Oh I'm sorry, I thought you wanted to clean the shit up but I digress, I suppose you simply wanta half ass do it !

 

Dont understand how taking my valve colver off is going to help me at all buddy.. the spark plug tubes are still there at the same height......thanks tho...

 

I’ve never removed the head but I guess thats the only way to get at a true clean up job. I remember seeing this kit designed to clean up spark tube threads where one sticks an umbrella thingy down into the piston chamber and opened it. Then a brush and vacuum cleaned up the threads without removing the heads.

 

Dumbass