kaganader

iTrader: (11)

Hey my 96 z28 started to misfire on idle and cruising driving after a 6day humid week and a 3 day rainstorm. And it seem to be dumping alot of fuel while misfiring since I could smell it coming out the rear (And I do have high flow cats)

I've replaced the spark plugs (NGK Tr55), MSD 8.5mm wires, and changed the opti. now the misfire seems to have vanish during normal and WOT pulls as it pulls like a rape ape, but will misfire and have the smell of gas coming out the exhaust during the 1st couple of minutes of start up, and dissapear after warmup and is driven. it gives code P0300 which is multiple random missfire.

What could be causing this as I've replaced what I thought could be the cause. could it be the coolant sensor or iat?

Thanks guys.

kaganader

iTrader: (11)

Anyone?

Spencer51X

I'm having a similar problem, it's not the coolant sensor because I just replaced mine and it's still doing it.

t/afrom504

i would say you have a vacuum leak in the intake manifold since I have the same problem. And then a mech. told me so but never gotten the money to fix it.

kaganader

iTrader: (11)

So your car also misfires and dumps fuel that you can smell out the exhaust on start up (and the few minutes after it idles)? The missfires go away after driving for a minute and it runs perfectly fine afterwards. It just feels like its missing power and bogs within the 1st few minutes of driving.

Would I be able to hear the air leaking out if I listen for it? And would I just need new gaskets for the intake manifold?

t/afrom504

Yeah it takes awhile for my car to start since my fuel pump is also going bad. But while cranking it I smell gas from the exhaust and even while driving I smell it. Im also getting the same P0300 code. As far as gasket material I think you have to use the black RTV kind but Im not sure. Check out the shbox.com site, it shows you how to replace the intake gasket.

BlownEarDrums

iTrader: (2)

Have you tried un plugging you O2's? Intake is not too bad, rent a vacuum gauge and check the numbers.

LT1John

check o2s.