Missives cylinder 3 and no eco mode?

[acolic]

Of course, one day into a 7 day road trip and I get a check engine light.

It’s telling me I have a PO303 misfire cylinder 3.

Also noticed that Eco mode is not switching on.

The truck still seems to be driving pretty well although the fuel economy is not where I expected it.

Considering I’m doing long stretches on the highway at a consistent speed.

I probably won’t be able to find a dealer until Monday. In the meantime I’d like to narrow down what’s going on.

I changed the spark plugs and all coils last Tuesday and I’ve been driving it since then without an issue.

I have some basic tools with me.

Any suggestions?

Thanks for the help.

 

[EdGs]

Was the plug change before or after the misfire?

 

[acolic]

I had seen the code a few weeks ago but it disappeared.

Then I changed the plugs and coils.

Then I drove the truck for a week.

Then it popped up again.

 

[Atcer2018]

How was the #3 cylinder plug when you changed them? How’s your coolant level? Any overheating? Trying to rule out a head gasket issue. Could be something as simple as weak coil pack or worn plug boots.

 

[acolic]

Coolant was changed two weeks ago and it looks good no overheating.

All coil packs changed with spark plugs.

The plug boot is the one in the coil pack?

If it was a head gasket would the adjoining spark plug also be misfiring?

 

[acolic]

Just checked the coolant in the overflow tank. Same level as when I started the trip.

I guess I could always swap the spark plugs and coils from the third to first cylinder and see what happena

 

[chopperman1]

Just checked the coolant in the overflow tank. Same level as when I started the trip.

I guess I could always swap the spark plugs and coils from the third to first cylinder and see what happena

Start with just the coil, don't do the coils/plugs at the same time. Process of elimination. If it stays with the coil then you know that's it. Next the plugs if it then moves you know it's the plugs. If it stays with the cylinder, well, lets hope not.... cam, lifters.... yuck!

 

[acolic]

Thanks

Number 3 cylinder is looking at the engine from the front, right side, second from the front?

Thanks

Alex

 

[chopperman1]

correct
front 2-4-6-8 rear passenger side
front 1-3-5-7 rear drivers side

 

[acolic]

Changing the coil didn’t eliminate the warning light.

I still have two hours until my next destination.

Truck working perfectly fine.

Once it cools down tonight, I’ll change the spark plugs.

I’m planning to cut my trip short, but I still have 12 hours of driving to get home.

 

[chopperman1]

It won't eliminate the light, you need to clear the codes for that. Stop by any auto parts store and have them do it.

 

[EdGs]

It won't eliminate the light, you need to clear the codes for that. Stop by any auto parts store and have them do it.

The parts store will definately scan it, but you might have to be the one to clear the codes. Had it happen to me once.

 

[acolic]

I cleared the codes, but unfortunately it’s still there.

I bought two new spark plugs.

Does the engine have to be cool to change the spark plugs or can I change it while it’s hot?

 

[Wild one]

I cleared the codes, but unfortunately it’s still there.

I bought two new spark plugs.

Does the engine have to be cool to change the spark plugs or can I change it while it’s hot?

You can change them hot,just don't get stupid when tightening them.
Just a heads up,if it is a cam/lifter issue,driving it 1200 miles home,isn't going to do it any favours,but sometimes you gotta do what you gotta do,just try and baby it as much as you can,get it into high gear as soon as possible,to reduce engine rpm.

 

[mtofell]

I had seen the code a few weeks ago but it disappeared.

Then I changed the plugs and coils.

Then I drove the truck for a week.

Then it popped up again.

This is somewhat concerning as it would seem to eliminate the plugs and coils... which is sounds like you're at least partially on your way to doing by swapping/changing.

With the code is it a flashing CEL? Those are no joke and flash for a reason... as in you should stop driving the truck according to the manual. Granted, I think a lot of that is to prevent damage to the exhaust system by dumping a bunch of unburned fuel into it.

I had intermittent flashing CEL on my 2014 (6.4 Hemi) and chalked it up to bad gas at first but it persisted. (Cover your eyes).... mine needed a new engine but long before as many miles as you've driven since the CEL I was getting massive shuddering/missing. The best news by far is that it's still driving fine.

 

[acolic]

Well the story gets better.

1/2 way through the drive the code and warning light went off.

Eco mode is working again.

And yes that was shortly after I refueld.

So at this point not sure if I should change the plugs.

With the light off I won’t know if I fixed anything.

 

[EdGs]

A CEL will definately make the truck not go into ECO mode.

I would definately baby it if you absolutely have to drive it.

I have read elsewhere on this forum that misfires connected to cam failures only happen under heavier load early on in the failure.

Injector issues can also trip the misfires, along with broken valve springs, etc.

Do you have any warm idle tick?

Praying for a solved issue for you.

 

[acolic]

Hi

No tick at all.

If I have to change the camshaft, lifters and all that, well, not thrilled but not the end of the world I’ve done that a few times.

Besides the coil and spark plugs, what else could this be. Just so I can start with thr simple stuff and work my way the catastrophic failure.

Fuel injector?

 

[Dodge 1500 4X4]

I read this whole thread and you've done every step to diagnose a misfire, possible fuel injector, switch #3 W #5 and see if misfire goes to Cyl 5, I would pull the valve cover off and check for rocker arm movement, possible valve spring broken but you should have a tick who knows!, don't run it in this state, cylinder orientation is looking at it from the steering wheel drivers side (left) passenger side (right)

 

[acolic]

Yup I will do that when I get home.

“cylinder orientation is looking at it from the steering wheel drivers side (left) passenger side (right)”

Just making sure I got this right standing in front of the truck looking at the engine, evens on the left, passenger side, odds on the right, drivers side.

#1 is the first one on the right closest to the rad?

Thanks

Alex