P0302 cylinder #2 misfire

L

localkineguy

Hi all,
I have a CEL that reads p0302 - cylinder #2 misfire. The guy at Advanced Auto said to just replace the plug. I didn't know which was #2 so I pulled both middle cylinder plugs and checked them. They look like white/grey-tipped which is "normal" according to most sites that I've seen so far. Also, I've just replaced the coils and plugs about 4,000 miles ago.
I was more suspicious of my EGR valve acting up since I had some rough idling lately. I pulled out my EGR valve and saw that it was all carbon'd. I couldn't clean it because the screws holding the assembly together stripped as I tried to loosen them.
bad Symptoms: rough idle
good symptoms: drives fine, just like before CEL. Recently got 33 MPG on the freeway.
Bottom line: What do you guys think I should do? And is it okay for me to make the 6 hr drive back home?
 
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Might as well replace the spark plugs; they're cheap. Then just reset the ECU and see if the problem replicates itself.
 
you can still get those screws off, same thing happened to me but i used vise grips to grab them and spin them, a pain i know but it does work
 
A bad EGR valve will cause a random misfire, not on one specific cylinder. The #2 cylinder is the middle one closer to your passenger side - I would try swapping your fuel injector in the #2 cylinder with the other one of the same color to see if the misfire follows the injector - if so, that injector is bad.

Specific cylinder misfires are a lot better than random ones because it rules out a lot of stuff like EGR valves, ignition coils, etc. You could still have a bad plug wire tho.
 
slavrenz said:
A bad EGR valve will cause a random misfire, not on one specific cylinder. The #2 cylinder is the middle one closer to your passenger side - I would try swapping your fuel injector in the #2 cylinder with the other one of the same color to see if the misfire follows the injector - if so, that injector is bad.

Specific cylinder misfires are a lot better than random ones because it rules out a lot of stuff like EGR valves, ignition coils, etc. You could still have a bad plug wire tho.
Click to expand...


it wouldnt rule out if it was the 2 cylinders it controls, however it doesnt rule out the whole thing if you get what i mean, the connector that leads to the wire could be severed, and the wire itself can be busted leading to that specific cylinder, although chances are unlikely (stripper)
 
Thanks Slavrenz. The problem is that I'm 6 hrs away from home with limited tools. I don't have my manual nor the know how to switch injectors...
You basically don't think its the plugs though?
 
Okay, CEL has gone away but my car is still idling kind of rough. I'll make the drive back home and try to address the problem there. I'm going to replace my EGR valve with the Canadian style one. I'll clean the MAF as suggested and I'll also take a look at swapping injectors. Is swapping injectors a difficult task?
 
thecrash91 said:
it wouldnt rule out if it was the 2 cylinders it controls, however it doesnt rule out the whole thing if you get what i mean, the connector that leads to the wire could be severed, and the wire itself can be busted leading to that specific cylinder, although chances are unlikely (stripper)
Click to expand...

I don't quite follow. Like you said, the coils control 2 cylinders each, and if one goes bad, it's gonna affect both cylinders.
 
slavrenz said:
I don't quite follow. Like you said, the coils control 2 cylinders each, and if one goes bad, it's gonna affect both cylinders.
Click to expand...

But if one of the wires is bad it will only affect 1. I say swap the coilpacks and drop in new plugs, it simple and can't hurt.
 
Well, I made the 6 hr ride back just fine, but just as I got off the freeway the CEL came back, same old #2 misfire.

It happened just before my oil light started flickering which brings a possibly independent problem. I just changed my oil about 1000 miles ago (about a week ago, I only make infrequent long trips). I checked my oil right before my long trip and it was full...I checked it immediately after I got home (when the engine was still hot) and it was empty...can I dismiss the "hot" checks?

The trouble with this problem is that the CEL flickers on at random times. It doesn't seem like the misfire occurs all the time.
 
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Symptoms seemed to have gone from inconvenient to serious. **** the misfire, where'd the oil go?
 
hornsfan10609 said:
But if one of the wires is bad it will only affect 1. I say swap the coilpacks and drop in new plugs, it simple and can't hurt.
Click to expand...

As I said originally:

slavrenz said:
A bad EGR valve will cause a random misfire, not on one specific cylinder. The #2 cylinder is the middle one closer to your passenger side - I would try swapping your fuel injector in the #2 cylinder with the other one of the same color to see if the misfire follows the injector - if so, that injector is bad.

Specific cylinder misfires are a lot better than random ones because it rules out a lot of stuff like EGR valves, ignition coils, etc. You could still have a bad plug wire tho.
Click to expand...
 
Checking your oil level when the engine is hot can be misleading sometimes... Did you check it again after the motor cooled down?
 
Even if the engine is still hot and you turned the car off and immediately opened the hood and checked there should be oil at least on the dipstick. It most likely would only be half qt low to a qt, not empty. There's no way that the pan should be empty. The motor cannot keep 4 qts moving around in the engine enough where empty is what you get on the stick even if the motor is still running. Where'd it go? Either rings are bad enough or enough rpms were used on that trip to burn it or there's a leak or both.
 
i12drivemyMP5 said:
Even if the engine is still hot and you turned the car off and immediately opened the hood and checked there should be oil at least on the dipstick. It most likely would only be half qt low to a qt, not empty. There's no way that the pan should be empty. The motor cannot keep 4 qts moving around in the engine enough where empty is what you get on the stick even if the motor is still running. Where'd it go? Either rings are bad enough or enough rpms were used on that trip to burn it or there's a leak or both.
Click to expand...

Not disagreeing, was just wondering. If the oil is a little low, and it's super hot & thinned out, then it can run off pretty quickly... I mean, if he went from 4qts of oil to less than 1 qt of oil, on a short drive, then I would think he would have noticed losing 3 qts of oil... maybe not. But that's a lot of oil. And I've never heard of oil burning that quickly. (shrug)
 
ucMP3 said:
Not disagreeing, was just wondering. If the oil is a little low, and it's super hot & thinned out, then it can run off pretty quickly... I mean, if he went from 4qts of oil to less than 1 qt of oil, on a short drive, then I would think he would have noticed losing 3 qts of oil... maybe not. But that's a lot of oil. And I've never heard of oil burning that quickly. (shrug)
Click to expand...
He said 1000 mile drive. I could see it being full, having a nice spirited or hwy speed drive like that and not having much oil left if you're burning or leaking it somehow. Lots of threads about burning oil in these cars before actually having to rebuild. Gotta stay on top of it if this is the case and keep it full until you rebuild.


my bad, he said 6 hr drive which is probably more like 500 miles. Better find out where it's going before driving back and be sure to have some to put in on the way back.
 
i12drivemyMP5 said:
He said 1000 mile drive. I could see it being full, having a nice spirited or hwy speed drive like that and not having much oil left if you're burning or leaking it somehow. Lots of threads about burning oil in these cars before actually having to rebuild. Gotta stay on top of it if this is the case and keep it full until you rebuild.


my bad, he said 6 hr drive which is probably more like 500 miles. Better find out where it's going before driving back and be sure to have some to put in on the way back.
Click to expand...

Reading fail on my part. I didn't realize it was that long of a trip. If it is burning that much oil, then a rebuild or swap is def. in the future.
 
damn, this does not sound good from you guys. So I drove a total of ~1,000 miles: 6 hrs each way. I just checked my oil level when I let my car cool and it was pretty dry. I added several quarts (don't know how many because I poured from one of those 5 qt containers) of oil to fill 'er up.
I noticed grease/oil buildup on the drive belt and timing belt areas.
I recently had my head gasket replaced because I was leaking coolant into one of the cylinders...I can't remember if it was #2 or #3. The guy who replaced the gasket for me said that the head was fine and actually...so was the old gasket. He put in a new one and everything seemed dandy after that.
As for the CEL, would a cylinder #2 misfire be caused by low oil?
I don't see drops of oil under my car so it must be coming out of the exhaust...how do I check this?
 
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