Help new Cam= rough idle

[mweber]

Help. I put a mild cam in my 2002 4.8 Sierra and the scanner shows an "all cylinders misfiring" code below 1000 RPM. Above 1000 PRM everything is fine.

:confused: :confused:

[jeremy96gase]

Putting in a differant cam changes your Air/Fuel needs.
You might need to upgrade to an aftermarket computer to change the Ratios.

[SoLid_PrAnkstA]

or adjust the timing...

and besides, what's the point in new cams if it's going to idle smooth?

[mweber]

Ok, I'm talking with a PCM programmer now. Uh the rough idle is ok, it's the misfire code that is a problem. Plus the truck won't pass smog with a misfire code.