blackfbird98

so long story short i finished a cam and heads swap on my 2000 z not to long ago. and it would misfire from time to time then run good for a while so I went to go get it tuned yesterday and the guy said that i have a massive vacuum leak somewhere and that my intake might be "cracked". i had them install new 42# injectors while i was there and had to limp the car home cause it was misfiring still (which has been an issue even before bringing it there) i took the intake off and inspected it thoroughly but nothing was damaged. it is an ls6 intake i shaved the entire bottom to have it fit over the ls1 coolant lines but my guess is that they are still not allowing the intake to seat properly. another thing is i hooked a scanner up to the car and am getting p0300 (for the cam) and a p0131 for bank 1 sensor 1 low voltage could that mean my oxygen sensor is bad and is causing it to misfire?? cehcked my plugs and wires and they are good so im at a loss and am hoping some of you can get me on the right track on what i should be checking.

jimmyblue

iTrader: (11)

Well, you do need the intake to seal. But whether
or not that's a problem is unclear / open. P0300 is
par for the course just with the small diameter
converter, let alone cam & mistuned. I'd ignore that.
Your sensor could be bad or could be cold, hard to
say about that.

I think you want any coolant lines rerouted and get
to where you're sure the manifold is sealed nicely.
Then if your idle hits target RPM you don't have a
gross leak. But that still seems like it could just be
an excuse from somebody who didn't want to spend
his time debugging a mess.

blackfbird98

the weird thing is the first time i started the car after the heads and cam it ran perfectly fine then after a week thats when it would hesitate and would misfire while driving but after a bit it would clear up and drive fine, after my tuner swapped my injectors it was actually worse then when i drove it there it misfired all they way back home. he was telling me that this " massive leak" was more prominent on the drivers side and that the signal for the drivers 02 sensor was barely showing a reading and that is why the car was trying to throw more fuel at it

CHADsterss

Check your spark plugs, plug wires, and coil packs. Mine did something similar after months of running just fine. It ended up being a few of the connectors in the spark plug wire boots weren't making a good connection with the coil packs.

blackfbird98

just replaced the wires, im going to triple check the plugs themselves and replace that faulty oxygen sensor. its just bizzare cause the car runs fine for a bit then after 5-10 min of driving thats when it will will start bogging and misfiring

D14HUGGER.ORANGE

O2 sensor will cause it to miss fire bad, I did heads and cam swap on my 99 ss drove a whole week with out getting it tuned which caused me to foul out both o2 sensor and it was running like ****. Got it to the tuner and he wouldn't tune it until the o2 sensors were fixed, also during my fast intake install I broke my map sensor in the back of the intake so had to replace that, so ended up being late to the dyno appointment and had to get my car tuned in the hottest point of the day :/ heart breaking numbers it was 94 degrees in the shop and 100% humidity. So driving it untuned will foul your o2s so check them and make sure the connections are dry.

AmarilloWS6

iTrader: (3)

I did the exact same thing to my c5 when installing a FAST and every few blocks my car would go Toyota style and and rev itself up to rev limiter wether it was in gear or not. It did it in a parking lot in first gear when I was pulling into a parking spot and my car took off like a rocket lol. After fixing it my MAP sensor still touched my firewall, I'm thinking about buying the relocation kit to stick it where the EGR would go.

D14HUGGER.ORANGE

I probably looking into that to. Mine does the same, feel like the flex of the motor will break it again.

10droped

iTrader: (1)

When I did my ls6 swap on mine I had to gentle tap the coolant lines down on all 4 corners, it caused the intake not to sit flat. I to shaved the entire bottom thinking that's what caused it to hit.

blackfbird98

So I have some updates, I ended up swapping the drivers oxygen sensor and the car drove a LITTLE better but lets say I'm cruising at 45-50 and try to give it more gas it will bog bad and wont accelerate. I got it back to the house and let it idle and when I listened close I could hear a howling/whistling coming from the drivers side of the intake but when I sprayed Carb cleaner around that side there was no change in idle. I'm at a loss guys I need ideas