I have a 95 Isuzu Rodeo with 3.2. the HC readings are 63 @15mph & 44@ 25mph. I did an oil change, replaced the plugs, wires, 02 sensor, and put in different fuel additives with each gas fill-up.
I noticed an increase in fuel economy. This was the fourth check for this go-around. Incidently I replaced the cat & O2 sensor the last smog 2yrs ago. I want to throw in the towel but I got a ton invested now. Please help.