Deciding to give up on Jeep

[Stan H]

No MIL. Not the same.

Mine would do exactly as you described, after changing the crank sensor it improved dramatically. Then changing the coil packs and plugs and injectors took care of the rest. Made mine run like a top.

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[Stan H]

Where is the sensor? I might swap mine just for fun.

Passenger side rear of motor right in front of the transmission . Easy to see . Let me get a pic.
Edit for pic:
Yes I have some old oil on there from the bad PCV valve I changed don't pay it any mind keep forgetting to wipe it off.

 

[23black]

Mine would do exactly as you described, after changing the crank sensor it improved dramatically. Then changing the coil packs and plugs and injectors took care of the rest. Made mine run like a top.

So I should be responsible for diagnosing and wrenching on my own vehicle still under the extended warranty? And for incremental improvements? On my dime?

Yes, four dealerships. No MIL.

Ill do the cam reset. Ill let y'all know.

 

[bleda2002]

Not surprised they aren't helping you, low amounts of misfires aren't triggering the light and aren't considered abnormal enough to fail warranty in their eyes. It's like eating oil, I think it was bmw that said 2 quarts every 5k miles was fine even though most of us would say something is wrong.

At 66k miles it's not unreasonable it's a sensor, coils, plugs, wires or something along those lines.

 

[ChrisNLA]

Not surprised they aren't helping you, low amounts of misfires aren't triggering the light and aren't considered abnormal enough to fail warranty in their eyes. It's like eating oil, I think it was bmw that said 2 quarts every 5k miles was fine even though most of us would say something is wrong.

At 66k miles it's not unreasonable it's a sensor, coils, plugs, wires or something along those lines.

I need to run J Scan on my truck and see how the misfires come back, but my truck runs perfect and I am pretty sure reports back similar misfire counts. Electronics these days are extremely detailed and many of the 'misfires' it may count are not any sort of misfire we could ever detect 'seat of the pants' style.

I have some screenshots at home of misfire data where my truck was running rough and had a flashing MIL.

 

[MPMB]

1800 sec is 30 minutes. It's not unusual for misfires to occur. A Pentastar engine idling at 625rpm is firing 3 cylinders per revolution. 10.4 revs per second, so that's plugs igniting 31x per second.

With parts built by the lowest bidder, not to mention quality of fuel, you'll never have 100% ignition.

At cruising speed, 1800rpm, it's 30 revs per second and plugs igniting 90x per second. Holding steady for 5 minutes, that's 27,000 plug ignitions.

If the engine operated at 99% effectiveness/efficiency, in 5 minutes you would have 270 misfires. In 30 minutes you have 21.

What you want to do is go drive it hard, and make sure you hit 5000rpm and over, and see what happens with the misfires. If your misfires shoot up in the 700s, 800s, 1000s in a couple cylinders, then you have a problem.

 

[23black]

1800 sec is 30 minutes. It's not unusual for misfires to occur. A Pentastar engine idling at 625rpm is firing 3 cylinders per revolution. 10.4 revs per second, so that's plugs igniting 31x per second.

With parts built by the lowest bidder, not to mention quality of fuel, you'll never have 100% ignition.

At cruising speed, 1800rpm, it's 30 revs per second and plugs igniting 90x per second. Holding steady for 5 minutes, that's 27,000 plug ignitions.

If the engine operated at 99% effectiveness/efficiency, in 5 minutes you would have 270 misfires. In 30 minutes you have 21.

What you want to do is go drive it hard, and make sure you hit 5000rpm and over, and see what happens with the misfires. If your misfires shoot up in the 700s, 800s, 1000s in a couple cylinders, then you have a problem.

Misfires are not common nor normal. Each one has a cause. Coils, plugs, sensors, fuel quality, injectors, and ratio. Lack of compression due to valves, rings.
Until anyone can give a definitive answer then there is no diagnosis for one common problem.
The only thing I can come up with is a faulty ecu. Or a faulty Z8 transmission. In all its worldwide applications it has, at best, a checkered history.

 

[Stan H]

So I should be responsible for diagnosing and wrenching on my own vehicle still under the extended warranty? And for incremental improvements? On my dime?

Yes, four dealerships. No MIL.

Ill do the cam reset. Ill let y'all know.

Your at what milage 66-67k yep I have and did and would.
At 66k unless you have extended warranty past the bumper to bumper ypur in your own. Most of my stuff acted up way after that somewhere around 110k but , just the other day a guy on here changed plugs , way lower miles than yours and plug was gapped way out of spec. That can affect alot of things changing all that aint too bad just time to get it done.

 

[ChrisNLA]

In all its worldwide applications it has, at best, a checkered history.

Strange, when I Google 'how reliable is the ZF8 transmission', Google is full of praise.

This isn't the 1970s. Misfires in an electronic fuel injection world are way different.

I think I know the fix, though.

https://www.toyota.com/

 

[MPMB]

Strange, when I Google 'how reliable is the ZF8 transmission', Google is full of praise.

This isn't the 1970s. Misfires in an electronic fuel injection world are way different.

I think I know the fix, though.

https://www.toyota.com/

I fixed your link.

 

[bleda2002]

Misfires are not common nor normal. Each one has a cause. Coils, plugs, sensors, fuel quality, injectors, and ratio. Lack of compression due to valves, rings.
Until anyone can give a definitive answer then there is no diagnosis for one common problem.
The only thing I can come up with is a faulty ecu. Or a faulty Z8 transmission. In all its worldwide applications it has, at best, a checkered history.

I think you need to reevaluate what you consider normal, as mentioned in 30 minutes you average 1 per minute. The engineers have set what they consider normal to be via the computer that monitors this constantly and will toss a light or code to indicate it's outside of parameters. Yes in a perfect system the number is 0, but 31 in 30 minutes does not indicate that any of the major systems are performing at a low enough efficiency to not be considered normal given we aren't in a controlled test environment when driving. Your engine is operating at 99.99885%.

 

[23black]

Not surprised they aren't helping you, low amounts of misfires aren't triggering the light and aren't considered abnormal enough to fail warranty in their eyes. It's like eating oil, I think it was bmw that said 2 quarts every 5k miles was fine even though most of us would say something is wrong.

At 66k miles it's not unreasonable it's a sensor, coils, plugs, wires or something along those lines.

Wouldn't it be nice if the dealership knew what component it might be?
No one wants to here my credentials but. I have been doing my own wrenching for over 40 years. A licensed Chief Engineer. An avid motorcyclist/mechanic. Specializing in European and British motorcycles. Vintage and new. My motorcycles are mostly modern injected models that need to be hooked up to GS911 and/or Tritech obd2 readers with live scan. Even to just bleed brakes or reset a service reminder.
A simple Google search for 3.6 Jeep misfire and what I see is this. Mostly cylinders 3 and 5 getting the most misfires means it's time for cam or complete engine replacements. That, after probable months of wrangling with short time employees in Jeep service departments. Wrenching on my own warranted daily driver?
I'll try a few more things, but not much more. Four visits and leaving my vehicle for weeks with no answer......

 

[DirkG]

If this is considered "normal", then I would sell the vehicle as "normal" and buy something that you feel comfortable with. This is going to bother you on a daily basis and frankly life it too short to constantly worry about your vehicle. You've clearly put enough effort into finding a fix. Especially on a vehicle that has an extended warranty.

 

[bleda2002]

Wouldn't it be nice if the dealership knew what component it might be?
No one wants to here my credentials but. I have been doing my own wrenching for over 40 years. A licensed Chief Engineer. An avid motorcyclist/mechanic. Specializing in European and British motorcycles. Vintage and new. My motorcycles are mostly modern injected models that need to be hooked up to GS911 and/or Tritech obd2 readers with live scan. Even to just bleed brakes or reset a service reminder.
A simple Google search for 3.6 Jeep misfire and what I see is this. Mostly cylinders 3 and 5 getting the most misfires means it's time for cam or complete engine replacements. That, after probable months of wrangling with short time employees in Jeep service departments. Wrenching on my own warranted daily driver?
I'll try a few more things, but not much more. Four visits and leaving my vehicle for weeks with no answer......

I'd probably say with the number you have that it's the computer adjusting parameters hence why it's not out of spec. As the tech mentioned the new ones have single digits misfires as well. If it was truly one of the other components I'd expect it to be much higher

 

[Stan H]

Wouldn't it be nice if the dealership knew what component it might be?
No one wants to here my credentials but. I have been doing my own wrenching for over 40 years. A licensed Chief Engineer. An avid motorcyclist/mechanic. Specializing in European and British motorcycles. Vintage and new. My motorcycles are mostly modern injected models that need to be hooked up to GS911 and/or Tritech obd2 readers with live scan. Even to just bleed brakes or reset a service reminder.
A simple Google search for 3.6 Jeep misfire and what I see is this. Mostly cylinders 3 and 5 getting the most misfires means it's time for cam or complete engine replacements. That, after probable months of wrangling with short time employees in Jeep service departments. Wrenching on my own warranted daily driver?
I'll try a few more things, but not much more. Four visits and leaving my vehicle for weeks with no answer......

Service the electric components first . For 700.00 you can buy all 6 coil packs. Spark plugs are 24.15 a piece injectors 5or 600.00 can remember was total of 1100 dollars that came in a box 6"×6"×12" long box .
Ordered from @AllMoparParts.com . Order correct everything perfect condition.
And was shipped within a week very quick.
Benny will take care of you and usually offers a shipping rebate

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