Cylinder 3 misfire

Just wonder if anyone would know a good way to go an not through parts at it to Fix the misfire. It only misfires after truck sits over night an start it in the morning. If misfires for about a minute then clears up. I’ve change spark plugs an wiring an still no change.

 

I had the very same symptoms when my head gasket developed a very slow leak coolant into the cylinder. I hope yours is not that bad.

 

Thank you for ur feed back! How did you find out that was the protests urs?

 

In my case there were other side effects: I was getting 24mpg instead normal 20mpg, SMOG test show NOx at 600 (the passing level was 601), bubbles and exhaust smell in radiator, coolant deteriorating very fast. As much as I hated this I concluded it was a head gasket and after opening the engine I found I was right - in my case Cyl number 1.



Funny thing the truck never threw any code. The bad thing was after the fix I was getting 20mpg again. I guess because of "water injection" the computer was compensating for leaning the mixture saving me gas and pumping NOx to the atmosphere.

 

it looks as if there was so much crap built up at the block - head gasket joint that the coolant passages were blocked at cyl #1

 

Had the #3 code. Same symptoms as yours. Swapped coils, then swapped spark plugs no change with either. Compression 180, 125, 135, 180. No exhast gas in the radiator or condensation in the oil cap. Long story short, I parked it for about 6-8 hours and pulled the plugs and used a cheap $30 Bluetooth endo/boroscope* and found just a little cresent of coolant in there, less than 1/4 of the piston covered. All others dry. Tore it down gasket leaking into #3 but the machinist revealed the head had two little cracks between valves in #2 and #3. New Chinese head, had machinist transfer all cams, valves, check shims etc, and bought a Japanese head gasket set. Put back together and it fired up like it was never sick. Machinist said not all heads crack, but worth having pressure tested.

A word of caution, I waited long enough diddling around with this that it fried the upstream O2 which cost another $200 in round numbers.


* something like https://www.amazon.com/Waterproof-E...a-571058046618&psc=1&ref=&adgrpid=68771709505