Cylinder 1/2 misfire - help please

Since a head gasket is suspected get a cooling system pressure tester, pull the plugs out, presurize the cooling system to around 15psi, let it sit for a couple hours, and look down each spark plug hole with a light for coolant in the cylinders.
If there's coolant in any of them you 100% have an internal leak, most likely the head gasket.

 

If you plan to continue pursuing & verifying this diagnosis yourself and your budget allows it, pick up one of these

DEPSTECH 5.0MP Dual Lens Borescope, 5" IPS Screen Endoscope with Light, Industrial Video Inspection Tool, 10ft Gooseneck Snake Camera, Waterproof for Wall, Pipe, Automotive

Depstech® DS580 flex-neck cameras. At $115** in my opinion it is an excellent value for the money. **Current price w/coupon applied, as of 2023-02-17

With a good-quality camera that also has side-view capability you will be able to pick up smaller traces of coolant leakage in the cylinder (like a single bead or droplet, or very thin vertical stream) much easier than just looking down the spark plug hole with a bright light. Also will allow you to detect odd-looking areas with excessive rust, or parts of a piston head or cylinder head/valves that look conspicuosly "steam cleaned" (bright, shiny metal where other cyclinders have plenty of normal carbon deposits.) "Steam-clean" appearance in just the affected area(s) of the suspected cyclinders can be a very useful secondary confirmation of a significant coolant leak into the cylinder.

Separately, a "block test" is something you can easily perform yourself if you want to verify the shop's results for "exhaust gases detected in coolant" -- here's the

$38 Block Tester BT-500 Head Gasket Combustion Leak Test Kit - Made in USA

cheap block-test tool kit. Less than $40 and no other special tools/equipment required.

Here's some footage from a Depstech® DS580 flex-neck cam -- from a recent inspection I did on my 2014 V6 4.0 a couple of weeks ago. While I think the YouTube-converted footage looks very good & sharp, the raw footage is even 10-15% sharper than this. (Because YT automatically downconverts & recompresses footage as it sees fit.)

SIDE-VIEW CAMERA / CYLINDER WALLS, HEAD GASKET, & VALVES (taken w/ DEPSTECH® DS580 camera)

https://www.youtube.com/watch?v=3S_iXxLhG8Y

FRONT-VIEW CAMERA / PISTON HEAD (taken w/ DEPSTECH® DS580 camera)

https://www.youtube.com/watch?v=P2Lp01qZ3MQ

 

Replacing a head gasket isn't rocket science. I assume the job is less labor intensive than the 4.0L V6 as you only have one head to remove. I don't know what the typical rate is for your engine. I have seen quotes for the 4.0L V6 range from $3500 to $5500.

With that said, if you are able to, I would do with Dm93 and GilbertOz suggested. A combination of pressurizing the cooling system while inspecting your cylinders with a borescope is your best bet for confirmation.

 

One other comment on head-gasket replacement in general. I am partial to "Schrodinger's Box" youtube guy's opinions on head gasket diagnosis, which is that in most cases, head gaskets don't "just fail" spontaneously. Usually there is a reason why they fail, and it's important to try to determine the reason before replacing it. If the root cause isn't found & addressed, a replacement gasket is likely to fail again.

OP's vehicle is a 2006, which (along with 2005) was a bad year for truly factory-defective 4.0L head gaskets, but as far as I've heard/read that known defect doesn't apply to the 4-cylinder 2.7L engine. All the more reason to try to find the primary cause. Perhaps in OP's case the cause was simply due to low coolant causing the engine to overheat? If there's a slow coolant leak somewhere besides the cylinders it would be good to track it down & fix it, or at the very least start paying close attention to how much coolant is being lost per 100 or 1000 miles driven.

Here are 4 of "Schrodinger's Box" guy's vids I found informative & useful for diagnosing & fixing a head gasket issue:

https://www.youtube.com/watch?v=uVn-IDi7da8

https://www.youtube.com/watch?v=AwiIpTIrBaE

https://www.youtube.com/watch?v=06l5jHMZt0Y

https://www.youtube.com/watch?v=nDf_IrEEbYg

 

I don’t believe for 1 minute it’s the head gasket. VC, tube gaskets and new ignition coils cost around $400.

 

IMO always get a second opinion on that kind of a job anyways unless you trust the mechanic with your life.

 

It failed a block test. Combustion gases in the cooling system mean blown headgasket, no way around it.

The coolant is low because it was leaking into the cylinders slowly overnight. When it starts up in the morning it chokes on the coolant for 10-20 seconds (poor idle) and then runs better after that.

Misfire codes didn't follow the coils when they were moved..

This is a pretty straightforward diagnosis

 

Well, I had the same thing happen 11 years ago… the overflow was empty so I filled to the full line and other than a flush the level hasn’t budged. VC gaskets and more importantly new coils have made all the difference. I wouldn’t be doing a HG, just yet but you may be right, I’m not doubting that. Let’s try to get it running the best it can and see what happens. I, mean he’s going to need the parts, anyway

 

Warm it up….

Drive it straight to a local dealer with trucks in stock…

Pick a new color vehicle

Trade it in….

 

Naw, not yet. I’ll have the op shampooing his carpet, soon

 

Man sorry Steve... Need the truck for work so I had to just eat the cost and go the head gasket route. It's getting worked on now and getting seals, pump and resurfacing done. Hopefully the car will last a long time now cause it's going to be costly. Appreciate everyone's advice and a special shout out to Steve104x4. Wish I could have followed your advice, but I just didn't have the time as I need the truck asap for work. This forum is hands down the best.

 

I’m sorry, too. Good luck! Is that the plastic or metal coolant by-pass pipe?

 

Looks to be the metal one.