StunnaSteve71

Hey what's up guys I have a problem I can't seem to solve I have a 99 z28 with a 2002 6.0 lq4 and I have a p0300 code I have replaced plugs and wires and replaced my o2 sensors and even swapped coils from another car and it didn't fix it. But heres the wierd part I unplug the mass air the misfire goes away and the idle smooths out, so I ordered the slp mass air and put it on hoping it would it fix it but it didn't the code came back on. Does anyone have any idea what my problem could be? I hope someone can help me thanks

INIT2WIN

iTrader: (8)

I have the same problem with my car. I've been through the stock maf, a SLP maf, and now on to a Delco Z06 maf. Still getting the same P0300 code as b4 also. I also changed all the plugs and wires and both O2 sensors! Its been driving me crazy!!! Interested in seeing what someone has to say about this.

StunnaSteve71

Hey init2win what's all done to your car? And does your misfire go away when you unplug your mass air?

INIT2WIN

iTrader: (8)

My car is a LQ9 stock bottom end with LS3 top end, cam, and full bolt-ons. I dont really notice when my car is missfiring, i just get the code all the time. Never really tried to unplug the maf.

StunnaSteve71

Mines just a stock lq4 out of a silverado with just headers and throttle body but you can feel my misfire with a rough idle if I unplug the maf the idle smooths out and the p0300 goes away but of course I have a maf code

INIT2WIN

iTrader: (8)

I might not be able to feel mine missfire as much due to the cam.

StunnaSteve71

I was going to call fbody central and see if they could help me with the problem or see if a tune would get rid of the problem

INIT2WIN

iTrader: (8)

My tuner said he thought my ECU might me on its way out when he tuned my car. But i'm not sure how to rule that out without an extra ECU.

StunnaSteve71

I fixed my problem, when I did the 6.0 swap I left the 6.0 sensor in like the can and crank sensor well I was doin some research last night on google and the search came up about how the crank sensor can cause a misfire so I was thinking that I didn't relearn the sensor so I brought it in today and relearned the crank sensor and checked the misfire data and it all went away and drove it on lunch and just drive it around it never came back and runs better