fuel economy gone??? Help!

[camccardell]

I went on a road trip this week and had a pretty good time, except for when I ran out of gas on the side of the highway with no cell service after only going 134 miles on a full tank of gas!
This happened on day 3 and I was just doing straight highway after the fill up.

What could cause this? The motor has been running a bit strange since about halfway up. I was doing a lot of highway (75 mph) but 21 mpgs? are you kidding me?

Looking for ideas

Thanks

 

[Dawg68]

What do you mean when you say the motor was running strange?

 

[camccardell]

like it would bog down when trying to accelerate

 

[scot in exile]

sounds like it is very rich

 

[Mittzy]

Check air filter - choking???
Plugs fouling??

 

[camccardell]

the air filter is clean, haven't pulled the plugs yet. I hooked up the laptop to the pcv autotune and applied the tables, and that didn't seem to help either. I tried resetting it multiple times during the trip as well before the empty tank scenario. It just is running thru gas very quickly.

 

[Steel]

I had a Suzuki do that once. The injector stayed stuck open. Unhooked the battery for 10 minutes to let the ECU reset. That fixed it.

If that is your problem, I'd suggest changing the oil after. Some of the extra fuel can bypass the rings, and get in the crank case.

 

[Rocket3Pilot]

First off, are you certain it was out of gas? How much were you able to put back in it? While it does sound like it's running extremely rich, I can't imagine it could be so rich as to only get 21 MPG. I've seen 28 MPG running a rich tune and cruising at 85 for a whole tank.

My understanding of Auto Tune is that it will progressively make the map leaner as you keep "accepting changes"?

What if you actually had fuel left in the tank but the filter was clogged or the fuel pump itself is failing so that it couldn't pickup the last gallon? Hence the bogging from starvation rather than to much fuel? Just a thought. Keep us posted though so we all learn.

 

[camccardell]

Well the tow guy showed up, but only had "about 2 gallons" which sucks because AAA is supposed to give you 5 but whatever.
I then ran 14 miles to the nearest gas station and put in a little over 4 gallons, so I'd say yeah, she was dry.

I should change the filter, shes probably the original.....

Side note, another 80 miles or so later the gas light came on, so I puled over to fill up again and I also added some fuel injector cleaner. Took about 4 gallons of gas too.

Ran like crap the rest of the way. Maybe the injector cleaner was actually doing something?

 

[kipper]

Maybe unhook the pcv set up and try running her as standard ,see if it's any better ?