ok i recently worked on my girls volvo since she uses it for work, for work not just to work. ok first off before i worked on it she was getting really bad gas mileage and her rpms were slightly fluttering....normally between 3 to 500 rpms now that i swapped out the TPS and the O2 sensor i somewhat fixed the rpm problem it only flutters 1 or 200 rpms but she still has bad gas mileage..... now my question is does the nonvolatile memory if that wasnt reset would that cause the continuance of the bad gas mileage since we still have that problem

 

After you replaced the 02 sensor, did you unhook the battery?

 

Need to unhook the battery to reset the system. Bad gas mileage can be lots of things. Mine started going south when I got all my gremlins worked out (so I thought). Turned out the fuel feed line from the tank to the pump was pissing only when I was driving until it let go 30 miles from nowhere this weekend.

Lots of things can cause bad MPG.

 

ok i fixed the rpm thing on the constant half and think i fixed the gas mileage but wont know till tomarrow but i noticed i still got a drop of assuming voltage and rpms drops at least 3 to 400 rpms when the electric fan kicks on. is that normal or am i correct on somethings drawing more power then it should

 

Sounds like you should look at vacuum leaks or your idle air control valve.

Regards, Andrew.

 

hmm i was figuring a power surge or something but thats a start...be awesome to get her gas mileage to where it should be