Cruising Vacuum Readings...MPG at 14mpg

Cruising along at say 65mph...light pedal...what your vaccum readings at?

Mine is about 10in on the highway, idle is at 15in gear/18 in neutral, decel it jumps to 21in, WOT Barely touch the pedal at drops to 0 or verrrrrrry near zero.

The reason I ask, is that highway mileage (95%) was 13.9 and 14.5 the 2nd tank. So either its as rich as Warren Buffet or the speedo is not counting the mileage correctly....or something all together different. The speedo gear was replaced about 2 years ago (5K miles.....maybe that much).

vacuum is measured in inches of mercury or in.Hg
sounds like something may be wrong, idle should be near 20 inches, decel should be around 23 inches.

So you make no boost at WOT? All the vacuum looks about right. If you aren't making boost check the bypass valve, make sure it closes when you goose the throttle. Make sure your belts are good and the tensioners aren't maxed out. O2 sensors could be bad, engine running too cold, need tune up plugs and wires?

Opps....wot boost is 12psi. Light pedal vacuum goes from 15 or so to 0......and then into the boost. Trying to figure out why the mpg is like poop.....or if it's maybe the odometer failing.

It's been so long since driving it, I forgot what the vacuum/boost readings were. The car runs like a bat outta hell. I hooked up the scanner, no codes.

I see you're located in southern California.....

You are most likely running "boutique gas".....

Thanks to the EPA the fuel companies brew certain blends of gas for different parts of the country for emission standards.....

I would try the simple things to increase MPGs like tire pressure and new air filter....

Ran it over to my buddy smog shop and put a sniffer in the tailpipes.

It's running rich. It will be the CO will be good, then slowing creap up, and then drop down some and the cycle repeats.

Thinking that the O2's are slow. They're newer, but from the old engine, which had a suspect back head gasket (white residue on the side of the block)

Gonna clean the MAF wires, and then check the voltages on the O2. I don't see a fuel pressure regulator on the EVIC.