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Misfiring, manifold glowing yellow - damage?

My '04 v6 wagon 100K will misfire in really damp conditions. Last fall after going through a massive puddle and today after sitting for a couple of days of warm damp foggy & rainy New England spring weather.

OBDII scanner is reporting cylinder 3 as the one misfiring in the fall, today there were a ton of codes (that I didn’t note).

So I made it about 2 miles from the house and had to turn back. No power, check light flashing. I had to put it in manual and keep the revs highish (3-4K). When I got home the exhaust manifold was glowing yellow, assuming one or more cylinders were passing fuel out to the exhaust and it was being burnt off in the manifold.

My question: could I have damaged any gaskets back there? This could be my imagination but I think I’m hearing a new noise that I’d normally attribute to an exhaust leak downstream of the muffler, very subtle - like a gentle light but rapid thud. I only hear this noise with my ear to in the front driver’s wheel well. There’s no ticking noise I normally attribute to leaks near the manifold.

My imagination or is it easy to damage something in the circumstances I describe?

Anyone got thoughts/ideas or experience of this? Thanks! /pauric

Now you know why a flashing check engine light means shut it off and tow.

Yes, it is very easy to damage something when you ignore check engine lights and don’t get problems fixed… and VERY easy to damage something if you continue to drive when the check engine light is flashing.

No telling from here what all the problems are now, but yes, you very easily could have damaged gaskets by driving the car under those conditions.

Had the problem been fixed when it first cropped up, I’d wager it would have been relatively cheap - misfire problems generally aren’t that expensive… but if not fixed, they can lead to VERY expensive problems. If you’re extremely lucky, your only additional problem over what the car originally had would just be an exhaust manifold gasket. But you may end up needing quite a lot more done…

Thank you, when you have a newborn in the car and your trying to make a doctors appointment… priorities are a little different.

Do you have any more insight on this issue? I do understand what a flashing check light means, I’d like advice on potential damage caused, how to tell if I’d damaged anything. For example, is the subtle noise I may be hearing my imagination or indicative of something else?

Thank you /pauric

What - exactly - did you do with regards to the cylinder 3 misfire back in the fall? One is left with the impression that you decided to ignore it.

Damp/wet misfires are usually not that hard to figure out - its something in the ignition system that needs attention. Often its just bad plug wires.

Read the codes again but this time do make note of them - and post them.

Yes, driving with a misfire this severe will damage all sorts of things. You could have damaged more than just gaskets - something more expensive like your catalytic converter.

Thanks! fwiw, the first time this did this, it lasted for a few minutes and didn’t happen again. I’m somewhat hesitant to take my car to a shop when the problem isn’t active.

Today was more prolonged and I absolutely had to make the 2 miles to home (screaming baby in car and unhappy mother)

I’m just trying to figure out what damage I did, how to tell if I did, etc.

I’m assuming the cause it moisture getting in to a connection at the back of the engine near the bulkhead (where cylinder 3 is located)

Many thanks /pauric

Yes, I ignored the first misfire issue once it went away )o;

off the top of my head, the codes were general misfire (p0300), misfire on one of the cylinders then
c0700. And another I can’t remember.

The car is now running fine and no new codes

And yes, I know I shouldn’t be driving it - family emergency.

Severe or chronic enough and it can damage piston rings. That overheating is not confined solely to the exhaust manifold and on out the back.

What would I do? Run a compression test just to know where I stood with the engine.

[i] I absolutely had to make the 2 miles to home (screaming baby in car and unhappy mother) [/i] 

 Keep in mind that it is bad to end up waiting for a tow truck, but it is worse if the driver has to tell you that you now need a new engine.  I am sure this is not a great time for an expensive car repair. 

In any case good luck.

I think I’ll just drop it off, some new code cropped up
P0138 02 Sensor Circuit High Voltage (Bank I Sensor 2)
P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
P0140 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)

So, I’m guessing the 02 sensor is triggering because of a leak. I’m definitely hearing a new “pfft” noise.

Thanks everyone for their help.

The only responsible thing to do at this point is to throw yourself on the mercy of a good mechanic. As the warm damp foggy rainy season has fully arrived in New England the misfire will surly return. You may not be so lucky the next time. A fire under the hood would ruin the day. The new noise could be a manifold leak, exhaust connector leak or a burned valve. You also may have destroyed the O2 sensor and or the catalytic converter. Best to find out before more bad things happen.

yeah, one of those things I guess.

I’m smelling odor in the cabin when stopped, so that points to a leak.

Thanks all /pauric