RANDOM MISFIRE

[TRC]

I have recently got a 2006 Chevrolet corvette base it has some gm hi tech adds to it. Think l91 heads and intake that goes with it. I went to the gm dealer for inspection and they said they needed to update software in the vehicles computer . Well ever since i got a engine light on which i took it back and then said it was mod and maybe needed a performance software upgrade for it. Well I did some research with a local performance specialist in the area and suggested Diablosport . He sold one to me I then upgraded the software and everything was great then 20 min and there it was again. Did diagnostics and read misfire code 0300. I called customer service and said for me to go to crm dealer. I called the dealer and he said it's probably just spark plugs the car has 17000 miles on it so I called another dealer that sold it to me and he said sounds like spark plugs. Then someone told me it had a upgraded cam. So i drove to the dealer I bought it from and he said that's a mild cam Diablo should have no problem adjusting it go put on some new wires. I'm frustrated. I don't want to have to pay another 400 bucks plus the predator then it be wires for 300. What's your thoughts can anyone help. Could it be a exhaust leak? Spark plugs? Cam? anyone run across this?

[johan]

It is unclear in your post but did you add a cam ?
If you did this code is normal and can be fixed with a custom tune.

[catsltd]

Simply raising the idle will almost always clear the p0300 random code.

if you run a cam and the idle is to low,then you will get misfire codes.
When i datatlog with my scanner,the misfire codes only appear at idle.

The confusing part is,that the cell will not usually come on if your sitting at idle when you first start it up.
Usually it happens after you have been driving for a while.
So your driving along and bang the cel light comes on.
So you think you have an engine problem,like plugs,coil or something.
Its not.

If you get a cel with a specific cyclinder misfire code,then you do have a problem with coil,plug or something.
At least this is how it works on our trucks.

[jah81592]

Or.... you can have your custom tuner raise the misfire monitor RPM to say 1200 before the misfire test is complete.-j

[HemiHorsePower]

Or.... you can have your custom tuner raise the misfire monitor RPM to say 1200 before the misfire test is complete.-j

That did the trick for me, allowing for a nice low idle.

[RTTTTed]

Another thing that causes misfires is injectors too big or pulse too long. My supercharger system causes misfire codes all the time. I had been running a '96 ECU because they didn't use a misfire counter in their programming. (Viper).

What was causing my misfires was a loose wire on the sub-computer causing the injector to stay on. Fixed it

Ted