hows it goin yall.. well a friend of mine has a 1990 civic, with i think just nitrus and a cold air intake. yesterday it started reving slow with a spitting sound and wont go past 90 mph... i thought it could be the fuel injection..? anyone have an idea what it could be?

 

What engine does he have?

 

You might want to check the ignition timing with timing gun and the mechanical timing by the timing belt.