truck will not go over 30mph when it does code comes up for multiple misfires and you
are unable to throttle down anymore. have checked everything for air leak. nothing comes
up. just replaces header gasket and exhaust manifold gaskets. code p300 keeps coming
up have also replaced fuel filter. believe it might be the fuel pump. any answers?
Maybe check your spark plugs too.
I have changed all spark plugs and wires.
Maybe your computer needs to be remapped.
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