Misfire/Engine Stumble w/ code

[nuQ]

A little background on my 2003 M45 w/ 112,000 miles. I purchased the M about 2 1/2 years ago and put very few miles on it. About a year ago, I did a lot of maintenance on it, including, new plugs, full fluid changes, coolant flush, and cleaned out the MAF. Well, like an idiot, I forgot to plug in the harness and tried to start it with the obvious results. Quick hooked it up, but the check engine light was on, and had it cleared many times but always comes back on. Up until a couple days ago, it ran fine, but when I started it yesterday, it had the noticeable stumble/rough feeling, especially at idle and lower RPM's. I got the codes read, and PO130 seems to be the one associated with this...oxygen sensor bank 1.

I stopped at an auto parts store, and they seemed to think the MAF might be bad and causing this from the cleaning, but it ran fine after the cleaning and this just happened yesterday. Anyone experience this code issue? I don't want to just throw money buying new parts. I have a tech that I trust, but I'd like to narrow down the issue before I bring it in.

Thanks!

[Jttoka]

If you have put on a couple thousand miles, I'd say no.
If it's been sitting with very little mileage since you cleaned it. Maybe

[nuQ]

It has been driven since the cleaning, and this symptom just started yesterday. I actually just came back from the parts store to have the codes read again, since I was not too impressed with the counter guy yesterday. This is what came up just now....and the M seems to be running worse as we speak...definitely a stumble when I rev the engine until it gets to the higher rpms...
Codes as follows;

1. PO300
2. PO507
3. P1212
4. P300
5. P1444
6. U1001

I was told #1 is multiple misfires. and #2 is idle air. He thought the other codes were proprietary to Infiniti since it wouldn't give a description on his reader.

Thoughts?

[Costee]

I'd suggest you clear all the codes and see which resurfaces before further action.

[nuQ]

I am going to give it a good check over tomorrow, but I'm thinking it is likely a vacuum leak somewhere. I'm taking off the engine cover to look tomorrow. Any surefire ways to detect a leak besides looking and listening?

[MaxBolus]

For reference:

1. PO300 - Multi Cyl misfire
2. PO507 - ISC SYSTEM (Idle Speed Control)
3. P1212 - TCS/CIRC (Throttle Control System - this cuts the throttle during slip/VDC events)
4. P300 - ? Same as #1 above?
5. P1444 - PURG VOLUME CONT/V (Evap Canister Purge Valve)
6. U1001 - CAN COMM CIRCUIT (Controller Area Network comm line error)

But before you go chasing these down, I agree with Costee and clear them and try again. As you suspect, a vacuum leak can cause all sorts of seemingly unrelated codes and could be the underlying cause here.
Although since a couple of these codes refer to the CAN circuit, you may also want to check for any obvious signs of loose/broken/crimped cables in the engine compartment (where you had the work done).

(And I used to just use a short piece of garden hose to listen for vacuum leaks, just BE CAREFUL you don't catch your necktie, dreads, or your good arm in any moving belts or pulleys!!!) (Also check the big flexible intake tube from the MAF to the throttle, I've found mine loose/leaking in the past.)

good luck
m

[nuQ]

Thanks guys....I'll let you know....

[nuQ]

PS....I also have a 2011 Hyundai Sonata with just 42k miles, and the M is so much quieter and smoother driving than the "newer" car! Night and day difference....not to mention so much faster...

[nuQ]

UPDATE....just had the M inspected and had the tech check into the misfire/code issue. It is definitely the #1 cylinder and it is either a bad plug, the coil or the injector. I had all new plugs installed less than 2k miles ago, so not sure I want to replace all 8, might just replace the one, and hope it's a cracked plug... Otherwise, they'll swap out the coil to see if it's that, and then on to the injector. Will definitely start with the plug....

[nuQ]

Is there a preferred ignition coil for the M? I will likely go through Advance Auto. In talking with a trusted tech today, the likelihood of a bad plug is very low, since they all are almost brand new....he is leaning toward a bad coil.. Thanks!

[lovemycarM35]

Dude your gong to to screw up your cats with that miss fire hope your not driving it

[Double E]

Agree from awful experience. Screwing up the cats will be a multi $K spend event for you.

[nuQ]

Turns out it was indeed a bad ignition coil on cylinder #1. Spent about $80 on the coil, and my tech installed for $15 dollars! Running perfect again, and all codes are cleared. I live in a PA county where we do not need emission testing, so as long as I don't have to sell the car to someone in a place that requires emission testing, I'm good!