Misfire On Multiple Cylinders unsure of issue

Many have reported issues with blown head gaskets, causing misfire symptoms.

 

If you're not losing any coolant, then you are probably OK. But misfiring can be caused by an overheating engine, causing head gasket issues.

Since you've changed the spark plugs, tested the coils, replaced injectors, then you'll just have to make sure those are all working correctly. When the plugs come out again, you may want to do a compression test.

 

Egr circuit is clogged

 

And this

 

Can I get a cheese burger with large fries?

 

Just for the record, there are six different ways a head gasket can fail, and not all of them will result in lost coolant or oil. So, yes.

 

Had a head gasket failure at 375k miles, and had it repaired. At around 450k miles, I am getting a misfire code for cylinder 4 along with P219A (fuel/air mixture ratio issue). I cleared the code 3 times and discovered that the CEL came back within 24 hours each time.

My mechanic tried swapping the coil to see if it followed it the way the OP did, and luckily, it did not. I got the CEL back after about 48 hours, but only the P219A code. Reset it and it returned again the next day. Another reset and now it's been a week.

 

Problem turned out to be clogged EGR ports in the intake manifold. A new manifold solved it.

 

New manifold? Really? They aren’t difficult to clean out; that’s surprising.

 

My mechanic tried and felt it would take him too long to do it, and so the cost of the labor would go beyond the cost of a new manifold, so I just threw a new one in there and took back the old one. I will try to clean it myself and use it next time this happens, and repeat the process with the new one.

 

20 minutes with a pressure washer and engine cleaner and labor would be too much? What is his labor rate?

 

He’s probably just not willing to do it. A parts changer most likely. Just wants to throw parts at it until the problem goes away.

 

For owners intimidated by the process of extracting the EGR and/or intake manifold component, maybe a hybrid approach: work with a mechanic will to pull the items and pass them over to the owner for cleaning. As long they're ok with the car sitting for a day or three, that'd maybe help.

 

An old post but I thought I'd add another possible source...

I have a situation with my daughter's car. She lives in about 45 minutes away and we see her often but she is busy right now so I haven't seen her in 3 weeks until quickly this weekend. As she was leaving, I noticed her car sounded just a little odd, but it didn't really register. The next day she had a check engine light. I had her check her FixD for codes (pretty convenient, by the way, for remote diagnosis... fairly limited device but good for some stuff). She had misfires on all four cylinders. The car had been in perfect running condition for the last 8 months when I did a head job (107K at that time... early. ).

It just seemed really odd that she'd have all four injectors, or all four plugs/coils go bad at once. So, EGR or fuel filter (?) seemed like the most likely cause. The next morning, I woke up thinking about something she said over dinner... She had purchased gas at a sketchy gas station because she was really low... I began to wonder... What if it is bad gas?

Anyhow, I drove up to SF to pickup the car so I could check it out. Plus, it was due for an oil change anyhow. On the way back it worked pretty well. When I got home, there were only 30 miles left in range so I filled up with a full tank. 3 hours later, after 0.7 miles on it, I started up the car and there was subtle, but absolute, misfiring. I drove it about 15 miles and then cleared the codes. I then drove it for about 45 miles and so far there are no codes.

So... Although I'm not 100% sure bad gas was the cause, I'm really beginning to think that this might have been the cause.... Just another thing to consider when you have a misfire problem....

 

These misfire gremlins on the turd generation car, you'll have a fun time trying to figure out the cause. It could be anything, and most of the time, it's a bad head gasket.