subbie racer

tends to happen alot when its cold out in the morning, but once warmed up its fine, so far i put new ac delco plugs iridium in gap to 0.40, new 02 sensor since it threw the code, i tested the coil packs with an ohmmeter tester, they were all the same, im thinking one coil pack is slowly failing but cant figure out which one it is

98 z28 camaro 6speed trans, mods are comp cam (dont know the specs, came with the car), intake, straight exhaust with no muffler (will be fixed soon)

O2Form

Might be a vacuum leak, check the intake bolts.

-Q-

iTrader: (10)

For a vacuum leak, also check the PCV hoses. They are very prone to cracking, and have been known to cause a P0300 code.

subbie racer

probably a stupid question but where are most of the vacuum lines located, and on the far back on the drives side, theres something blocked off on the valve cover with a rubber boot but it dry rotted and broke

and also could a egr delete cause a misfire? they took it off the car

-Q-

iTrader: (10)

The vacuum lines (PCV) run from both valve covers to the front of the motor and then go to the intake manifold and throttle body. That rubber boot you are talking about on the driver's side is part of it, and if it's cracked and dry-rotted, then it's almost surely leaking there.

What kind of PCV do you have in place now? You can replace those PCV lines with fuel line if you need to...

2xLS1

iTrader: (25)

You do know that just about any cam other than stock will set false misfires if the misfire tables haven't been changed in the tune.

Whiteaw57

iTrader: (2)

Great point here ^^^ what type of tune does it have in it?

-Q-

iTrader: (10)

Yeah, this is absolutely correct. The misfire tables will need to be desensitized for pretty much any cam. I must have glossed over that part of your original post...

subbie racer

i found one line on the passager side, it needs to be replaced, i tried finding where the other hose went from the drivers side but couldnt find it, can anyone post a pic on the drivers side of where it should be hooked up to.

and as for the tune, i have NO idea if it even has a tune, i cant even turn my a.c on somtimes cuz it'll stall out my car, so i messaged someone on a site called tamparacing.com who does tuning and a dyno so im gonna see how much its gonna cost me, i found one place thats $400 for a tune

Whiteaw57

iTrader: (2)

If its a reputable shop go with that. Thats about the going rate. id say thats your problem for sure if its stalling with the ac on. the pcv sysem hose for the drivers side is at the rear of the motor on the valve cover. Imagine if you took the passenger side off flipped it around and put it on the other side. rear facing at the back

subbie racer

another shop quoted me $460 with dyno time not so bad

and i found a pcv diagram so tomorrow i'll get under the hood and see whats going on

subbie racer

the whole pcv is pretty much blocked off -.- caps on both side of the valve covers the pcv line was bent around and looped under where it comes out near the intake, gonna go to chevy today after school and find out how much this will cause since im sure i wont be able to get it from adv.

-Q-

iTrader: (10)

Man, that sucks. You need some sort of PCV on your motor, but that dealer is probably going to charge a fortune for the new lines and PCV valve....

subbie racer

$137 for now i think im just gonna throw on those small air breathers you would normally find on the old school cars

9911UZ28

iTrader: (4)

I just rebuilt my motor and put it back in. My P0300 code was caused by a Loose Spark Plug wire on #1 and a cracked Vacumn line to the rear hookup on the pass valve cover.

Took care of both issues and the problem has not returned yet