gas millage

Hi there,

The first thing to do is make sure that the engine is tuned correctly and in good condition. It only take a faulty vacuum hose or the ignition timing to be slightly out and your fuel consumption will go out the window. Start there first.

Mark (mhpautos)

I have looked at everything and it looks good. No vacume hoses are off. I want to know if a bad O2 censor will make my gas millage to go lower.

Hi there,

Yes it will, these will fail and the only thing you may notice is a gradual decrease in economy.

Mark (mhpautos)

I put a new O2 sensor in and I have not got any better gas millage. Do you know of anything else that will make my gas millage go down.

Hi there,

If you are sure all the relevant tune up items are correct, i would be doing an exhaust gas analysis.

If you see a higher than normal reading on the hydro carbons you may have a problem with an injector, you can have a injector service done on car"it is a good idea to think about this every few years as they are often forgotten about completely. Also a skilled operator will be able to read a live data read via a hand held good quality scanner, this may show up something. If there are NO codes set (you have checked?) you don't always have a fault light on with a set fault code. Also check things like valve clearance's coil out put voltages, High tension lead resistances, and get a run on a oscilloscope, as that will be able to do cylinder balance checks, check KVa's and ignition pattens, all helpful in diagnosing tune faults,

Mark.