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disable the injector for each cylinder , one at a time , comparing the RPM 'drop' to the others.sounds like you should notice a difference in each cylinder Except #5. Was the plug you replaced from #5 fouled with oil or gas , or was it realy clean compared to the others? Compression test may also help rule out certain issues , as will a simple vacuum gauge observation. May want to consult a shop for diagnosis if you don't have the necessary tools. It'll be cheaper than lots of unnecessary parts. Good luck.
What is an injector drop test
disable the injector for each cylinder , one at a time , comparing the RPM 'drop' to the others.sounds like you should notice a difference in each cylinder Except #5. Was the plug you replaced from #5 fouled with oil or gas , or was it realy clean compared to the others? Compression test may also help rule out certain issues , as will a simple vacuum gauge observation. May want to consult a shop for diagnosis if you don't have the necessary tools. It'll be cheaper than lots of unnecessary parts. Good luck.