TheNightWolf

So my car has always had the misfire from first to second NLS as everyone else has complained about it seems....
But that's not what this is about
Heres a list of what I have done to my balt and information about the miss will come after.
ZZP intercooler and piping, MAF relocation, NO BOV.
Muffler delete.
K&N filter drop in.
ZZP Tune, with the MAF relocation and stuff.

So it drove fine for the first week, a trip on the dyno and a trip to the track along with a few highway pulls.
On friday after filling it up at Mobil, 93 octane obviously, it misfired a couple times, mostly under high RPM shifts, no big deal, thought nothing of it. Then on my way back home which was a 3 hour drive that day, I attempted to pass someone on the highway, immediately misfires from hell and the car went into limp/noboost mode. Pulled codes at Advanced auto, got 1 and 4 misfires. and MAF codes. Unhook mass air, and it ran a bit better still missed at higher RPM
So....saturday night I went and put new plugs in it, a heat range colder, and it helped a little bit....not enough to cure it. this time the miss was on cylinder 3 only.
So sunday I did a compression check, all cylinders at 145 psi no variation.
So I take the 3 coil move it to cylinder two.
Misfire stays on cylinder 3.....move plug to cylinder 2 and the misfire moves to 2.....new plug.....still misfire on cylinder 2....move coil to cylinder 1 now, cylinder 2 still misfiring...
I'm at a loss now.....nothing seems to help, I even went back to a stock tune....so either something internally is messed up, or I'm missing something entirely...
Any input would be greatly appreciated....even the master techs at work are baffled by this...

Some input from a guy at work was it could be a valve spring...
Another tech said it could be a bent valve.....but that would screw my compression readings I think.

CannonBalt

Check this website for your codes, and possible causes/fixes. It helped me when I had my misfire (P0300). Turns out i had a vacuum leak, causing the car to run lean... Fixed the leak and it went away, Also have a bad 02 sensor post cat which can cause a misfire as well.

OBD-II Check Engine Light Trouble Codes

TheNightWolf

If I had a vacuum leak would I notice it as a boost leak as well?
I can check for a vacuum leak, but it idles fine....even just using the Map sensor without a MAF I get misfires, wouldn't running just off the MAP narrow it down?
And as far as the 02 sensor, I want to be sure its that before I throw 100$ at a sensor....It does seem to have a dead spot occasionally when takin off, but the fuel trim isn't erratic, and the sensor voltage is reacting to the RPM

CannonBalt

My leak was PRETTY huge.. i had a 1/4" hole in a line and was sucking massive amounts of air, My RPM's stayed around 930 at idle... but fluctuated very slightly, until i put my thumb over the hole and you could hear it even right out.

I checked my MAF sensor while the car was idling by unplugging it, and the car died right out.

As for the vacuum leak noticed as a boost leak, I'm not fermilliar with the LNF, but my LSJ I was boosting fine... If your car is hesitating on acceleration that can be a sign of a bad sensor somewhere.

TheNightWolf

Since the entire manifold is filled with boost I think I would notice a boost leak if it was a vacuum leak..
My car stays running with the MAF unplugged and runs the MAP as the backup as most GM's to to my knowledge..
Its slight and isn't all the time....I'll check the voltages again tomorrow while I drive to school/work.
see if there is anything weird about it.

CannonBalt

It probably depends on how big the leak is. What codes are you throwing exactly?

TheNightWolf

p0302
that's not pending.


Pending codes I'm getting are high circuit IAT p0113 if I remember right

and a p0100
Those are pending and randomly come and go....

rogersj

have you tried cleaning the maf?

TheNightWolf

I can try it tomorrow.
Its a pain to get to since its relocated at the TB but I should be able to sneak down there somehow and get to it.



But, me unplugging the MAf and still getting the misfires leads me to believe its not that.....Just my thought...

sound26

do you have find a issue ??