my hatch 89 failed for to high hc what you guys think could bring this down!
has new diz cap n rotor with new ngk wires n spark plugs
umm runs clean drives super nice the timings at 14deg now i failed high hc @ 16 so im hoping bringing down to 14 will give it some luch
it has a k&n just cleaned it will any fuel injectors additives make it worse ? any suggestions i appreciate them thanks

 

i remember when i failed for high hc's i just the basic tune up like: fuel filter, spark plugs, spark plug wires, oil change, cap and rotor and also replaced the o2 sensor and the next time i went in it passed.

 

The cat was backwards!