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p0300 code w/ N* tb lq4 and tre 80lb injectors

40thAnnGTP2002

40thAnnGTP2002

New member
hello all fellow w-body people I am trying to fig out a p0300 random misfire code I have. First off, it is ONLY at idle and no other time. 2nd)I have the following mods; Gen v w/ a 2.8 and KYGTP Beltwrap(THANKS AGAIN STEVE!) and Northstar Throttle Body w/ LQ4 MAF on 16* timing with yella terra 1.95 roller rockers and crow 105# springs w/ zzp modded retainers and comp valve locks, also have Tre 80lb injectors and a Tre 255 fuel pump with a caspers hotwire kit. I am on E85 and also a milzy fsic fb 101 fmhe flowjet ic pump. I have factory Acdelco wires and AL 103 plugs gapped at .045. I don't have an EGR Valve bc I deleted it and I also deleted Evap solenoid. Car runs great other than the random misfire, I can feel it but have no clue whats causing it bc as soon as I give it gas-it goes away. 3rd) I have tried the following; diff plugs and wires, maf, map, idle air control valve, sprayed brake cleaner around intake and sc for leaks and I have 0. also tried all diff coilpacks, icm, and even reverted back to l67 throttle body. I have used tiny tuner and played w/ inj offset vs battery voltage and low pulse width inj offset vs pulse width vs map. ANY AND ALL HELP WOULD BE GREATLY APPRECIATED!!!
 
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with most aftermarket cams, the vendors recommend disabling the P0300 code because of the random misfire. I would suspect your combination is setting it as well.
 
I didn't see he has a cam, only high lift rockers. I agree there's something about the combo. maybe just enough lift on the stock duration that allows enough fresh air past to trick the PCM into thinking there's a misfire
 


Iridiums are no good with boost, copper works better for us. It's been awhile for me but I only remember using 103 once I had ported heads and is3 can and when I was turbo, but like I said it's been awhile.

I agree try raising the idle 100 rpms
 


It's more likely that it would be a clogged or streaming fuel injector.
What is the history on your injectors? You may want to remove the coil packs from the ICM and flip your rails upside down and crank it over to see if one of them is bad
 


Didn't a guy just go through all of the usual suspects the other day and had a loose reluctor on the balancer, re-tightened it and put some locktite and all was good with the world again?

Jeff
 
there was a guy,,, but hes failed to update the thread.

he got it figured out, something with the injectors in TT needed to be changed cause they are so damn big.
 
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