need help ASAP, car will not stay on

[stewartfn18]

so i just did a write on my pcm to make some changes. after the write, i waited the 20 sec like it says, and tried to start it. it starts, so the pcm is not bricked, however immidiately after it starts it dies. i have no clue whats going on.

[SappySE107]

Did you do a complete write with a VIN that doesn't match your car? Sounds like a VATS issue to me. You can disable VATS if you want, or deal with the relearn process.

[stewartfn18]

i do partial writes. anyway, it turns out that for whatever reason, after the write it decided to set the engine oil pressure and A vehicle theft code. i cleared the codes and it started with no oil pressure issues. on a side note. i wrote the pcm with the modified maf tables that we discussed on GAGT. still getting upwards of 4* of kr. i noticed that the afr in pe was around 12.5. when i dropped the new motor in, i had to regap the plugs to .060. when i was doing this one of the electrodes broke so i had to get a new one so 5 of the plugs are ~50k old and 1 is ~12k old. could this be the problem?

[SappySE107]

Anything is possible. Can you tell which cylinder misfires or is it random? if its random, id guess its not a single plug causing your problem.

[stewartfn18]

well its not misfiring enough to set a light. i did get the p0300 code a while ago which is random misfire, but i was told by a few differnent people that have cams that thats normal with a cam and to just turn the light off. could also be cylinder blow by?

[SappySE107]

I think its just the tune personally. Cams don't cause misfires unless they aren't tuned properly. You can do a leakdown test to check your rings.

[stewartfn18]

would blow by cause kr like im getting though. i would assume it would cause kr but im not really sure how much. i guess it would depend on how bad the blow by is. also what do you think about having 5 older plugs and 1 newer one. you cant isolate kr to one specific cylinder. but if those 5 or so plugs are bad then it would give noticeable kr through the pcm i would think

[SappySE107]

Blow by causes the oil to get dirty VERY quickly. If you want to know for sure, do a leak down test. Theory and guessing are poor replacements for testing. If you are worried about the plugs, test them as well. I have had one cracked in the porcelain cause random KR on my 3.4 DOHC.

[stewartfn18]

well i just changed my oil. i went 5k on conventional and it honestly didnt look to terribly dirty, so i doubt thats my issue now. anyway i picked up some ngk tr6 plugs today. i heard that iridium plugs are bad for high performance apps because the electrode it too small

[SappySE107]

Whoever told you iridium is bad for racing apps is wrong.