p0300 agrivation/rant

calendap

so this isn't really a question more of a rant on how aggravating the p0300 code is. just to give you a little back round on my car, an the events leading up the problem.

I bought it used with 25000 miles on it 1 owner its 2011 an bought the car in October drove it around for a bout a month before I put it away for the winter. over the winter I had the dreaded steering lock failure witch I got fixed still under the factory warranty. about a week or 2 after I got that fixed in April it was a cold morning an my cel popped on got the code reed an sure enough its was the dreaded p0300 after a couple days the light cleared. the light has been coming on an off since then staying on for about a week an clearing for about a day. I notice a slight misfire on cold start up every now an again but that about it the car runs fine other then that runs fine, all the way up to red line the cel doesn't flash I cant feel any misfiring

since then ive installed the stillen gen 3 intakes an the nismo cat back the cel still come on an off i really don't want to bring it to the dealer because from what ive reed on the forums they pretty much just throw parts at it till it stays off. i tried cleaning the mafs with no luck.i also reed some where on hear that the parameters for detecting a misfire are really tight so im not supper worried about it

but something else i think i noticed was that the car seems slower when the lights on maybe its just me i don't know lol. but hear is my theory i know the
p0300 kicks up the idle, but i wonder if it pulls some timing an add a little bit more fuel to lower the chance of a misfire, an there for making less power.

i was just wondering if any one els has had a similar observation or opinion

ps:i plan on getting coils an plugs done an if that doesn't work, just getting the uprev an turning off the cel with that as long as i only keep on getting the misfire at start up.

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DOOMMONKEY777

Could it be a shaft position censor? Reading wrong rpm and then selecting wrong timing and firing, check the difference btw the two rpm readings using Osiris.

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Jordo!

First look for vacuum leaks -- could easily be the cause of a lean, random miss.

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calendap

Thanks for the replys guys, I'm definatly going to recheck for vacum leaks. Maybe I can reposition silicon couplers for the gen 3 intakes. An re tighten the mafs.

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savage916

Was it a leak? I'm having the same problem

Gixxerman

I left my Z in my garage for a week and decided to take it out for an evening ride with the wife last August. After cruising down the road for about five minutes, my Check Engine Light came on, I thought it was the gas cap. After weeks of trying everything from checking for vacuum leaks, adding Seafoam to the fuel, cleaning the MAF's, .... I took it to a shop that specializes in Z's. My mechanic did everything I did and more with the same results. After eight days in the shop, a set of spark plugs and four hundred dollars later, I still had the same problem. To make it worse, the car ran better than it ever had. The Check engine Light remained lit, so I took it upon myself to change the Coil Packs with the same results.

Fast forward to October, after leaving work, my car went into Limp Mode. Luckily school was out, I drove the car to the dealership. I was informed that my Timing Chain was off twelve degrees. Another week in the shop and $1,500.00 later, the car is running extremely well.

lj909

So the question is, how did your timing chain become 12 degrees off?

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