P0171 Honda -

Question

I had both codes pop up I recently changed my spark plugs to a denso tt platinum plug and noticed a big decrease in gas mileage then my check engine light came on with p0174 and 0171 so I changed the plugs back to a ngk v power and the check engine light has now gone off just wanted to know could those plus have caused the problem

Answer 1

fuel pressure should be @ around 35psi