07 M45 Misfire

[Waders]

My M45 just started misfiring. Ive notice it a couple of days ago when i stopped at a light, there was a jerk and idle drop a couple of times but now it stutters on idle and it sounds like a boxer engine when i give it gas. Sounds like there a cylinder thats not firing. The service engine soon light blinks from time to time. What do I check first? Is there anyway to see the codes without the obd2 scanner, I know how to reset the ecu but is there a way to see codes. Thanks in advance

[steve_c]

My M45 just started misfiring.....What do I check first? Is there anyway to see the codes without the obd2 scanner, I know how to reset the ecu but is there a way to see codes...

The best way for us to help you is to give us the code(s).
Basic OBDII readers are cheap, you can pick one up from any auto parts store!
You might even be able to borrow one from a parts store to check your codes.

If your light is flashing, that could indicate a critical fault may exist, and that you might be doing harm to the engine and /or its components driving under those conditions.

[Waders]

What ill do is go buy a scanner and come back with the codes. Its really running rough.

[Waders]

When the light is sometimes flashing and stops, what does that mean?

[Ilya]

It's flashing the code...think of it as morse code. P0304 code means it blinks 3 times long, then blank, then 4 times quickly, etc.

[Waders]

Alright yeah, i was thinking that was it, Ive done this to other cars ive own (ecu codes). It was kinda hard driving and trying to figure out what the code was. Im gonna drive it to my mechanic in the morning. Will the code be stored in the ecu, cause its the CEL isnt on when i start the car, it just start blinking and stops after a while.

[Ilya]

It may show up as a pending code, but that's weird that it's blinking if it doesn't have the CEL on in general.

[cjcarbone]

The check engine light blinking means that there is damage to the catalyst likely- obd2 does not blink out codes.

[Ilya]

The check engine light blinking means that there is damage to the catalyst likely- obd2 does not blink out codes.

Not sure about the catalyst, but as far as OBD-II blinking out codes, it absolutely does. On my 99 Maxima, without a code reader, what you used to have to do is turn a screw on the ECU and it would blink the code for you.

That was a 99 Maxima, so granted I'm sure there is no screw to turn on an M, but OBD-II most definitely does flash codes to the owner.

That's just a general little factoid...might not be related to this car at all. But if it looks like it's repeating a pattern, it's likely flashing a code which PROBABLY points to the catalyst.

[Waders]

Just went and started the car and it sounds fine, no misfirintg. I took off the neg battery last night and started it. Im not sure what to do, probably sure it might be a coilpack or spark plug. Ive ordered some spark plug but I dont know if its a hard job changing them. Might just take it to a mechanic when i get the spark plugs

[steve_c]

My M45 just started misfiring.....What do I check first? Is there anyway to see the codes without the obd2 scanner, I know how to reset the ecu but is there a way to see codes...

The best way for us to help you is to give us the code(s).
Basic OBDII readers are cheap, you can pick one up from any auto parts store!
You might even be able to borrow one from a parts store to check your codes.

If your light is flashing, that could indicate a critical fault may exist, and that you might be doing harm to the engine and /or its components driving under those conditions.

cj is correct. A light that flashes while driving indicates a critical condition in which continued driving is not recommended.

[EdBwoy]

Just went and started the car and it sounds fine, no misfirintg. I took off the neg battery last night and started it. Im not sure what to do, probably sure it might be a coilpack or spark plug. Ive ordered some spark plug but I dont know if its a hard job changing them. Might just take it to a mechanic when i get the spark plugs

It's not terribly hard to change most of the sparkplugs on an m45 and although I can do it blindfolded, it's still not my favorite pastime. Also, replacing sparkplugs isn't a bad idea at all at a certain mileage, but at around 80 Dollars for parts, why do it if you don't have to?
If you can, I'd also recommend getting the codes read before you buy any other parts. There should be something stored or pending even if the light is not on. When you disconnected the battery the codes could be reset but from what you're describing, I bet it will be back soon.

[Waders]

Update: I drove the car this morning all was fine, but when it reach normal temp it started misfiring. It sounds like a boxer engine, so I brought it to the mechanic and he said if the cel lights flashes its usely a misfire. So hes gonna plug it in for codes and we will see from there. Ive ordered a set of plugs to get them changed. Might be a plug might be a coilpack. The misfire only occuring at normal temp and not when cold makes me think it might be a coilpack. Had the same problem with my Gtr. Ill let you guys know what happens, it might help some other guy having the same problem in the future.

[BlackCat81]

Update: I drove the car this morning all was fine, but when it reach normal temp it started misfiring. It sounds like a boxer engine, so I brought it to the mechanic and he said if the cel lights flashes its usely a misfire. So hes gonna plug it in for codes and we will see from there. Ive ordered a set of plugs to get them changed. Might be a plug might be a coilpack. The misfire only occuring at normal temp and not when cold makes me think it might be a coilpack. Had the same problem with my Gtr. Ill let you guys know what happens, it might help some other guy having the same problem in the future.

Easiest thing to do to see if it's a coil (which it probably is) is swap coils to a different cylinder and see if the misfire moves with it.

[Waders]

Update: It was the coil on #7. Put in a new one and now it runs great. I always felt the car had a little stutter or a little loss in power, but now I dont feel it anymore. Is it possible that the coil was doing this, just before it failed? it might just be a placebo but it seems to run much smoother now.

[cruzad3r]

were you able to scan for code and if so, what was it?

[BlackCat81]

Update: It was the coil on #7. Put in a new one and now it runs great. I always felt the car had a little stutter or a little loss in power, but now I dont feel it anymore. Is it possible that the coil was doing this, just before it failed? it might just be a placebo but it seems to run much smoother now.

Absolutely. If the coil is weak/inop, then the cylinder is dead or weak, which means it's sister cylinder is dragging the weight of an unfired piston. On a small displacement V8, it can be really drastic feeling.
Depending on how long it was misfiring for, it probably wouldn't be a bad idea to throw a set of plugs in it. Since cylinder 7 wasn't firing, it was just covering the spark plug in unburned, raw fuel for who knows how long.

[Waders]

I didnt get the exact codes but the mechanic said "misfire cylinder #7".

Yeah I got a brand new set of plugs and I going to change them probably tonight.

[Datniqqamycole]

I've changed spark plug on cylinder 8 and just replaced the coil pack. Erased code and few minutes later code came back. Cylinder 8 missfire. Help=[

[MIG_45]

Have you tried swapping another coil from a different cylinder to see if it followed the missfiring?