Crap MPG question

[msggunny]

Ok,

97 5 speed Disco, new plugs, new wires, new air filter (paper element), new oil (RP 10w 30). 73K on the clock. Not driven hard, at least not by me.

Historically we have gotten between 19 to 17 MPG.

Wife fills up today and does the math. 12ish MPG. She has a heart attack and throws the whole agreement we had about if it becomes too expensive to own we get rid of it.

No check engine light on, it runs fine, exhaust doesn't smell like its running rich, no black smoke when i accelerate hard.

Unless there is a code that isnt triggering the "check engine light" then everything is running correctly

I dont know much about OBD II systems, could there be something not working correctly and no check engine light?

The wife is from a tropical climate and thinks that 60 is cold, so she starts it and lets it idle for at least 10 min in the morning before she leaves for work, and the same thing before she comes home so its nice and toasty inside.

I suspect that this is the culprit. Letting it idle for a long period of time can consume a significant amount of fuel and make for the shit MPG calculation.

Any ideas?

[LANDY96]

I think it will have some affect, but it shouldn't be that dramatic. I am on my 2nd 5-speed disco. First one was a stock SE7 with 255/70/16 tires(bigger than stock). I got 13-14 with city driving, and 17-19/20 on the highway. That is going 67-70 mph. No lead foot here people! The second one is a 96 as well, with a 4inch lift. 32" tires. I get @12.5-13 combo driving. I havn't checked it on the highway, but with a full rack I got about the same at around 65mph. I have noticed that O2 sensors on there way out will kill your gas milage too. I had a check engine light come on, and then turn off later. The stored code was an O2 sensor problem. Mpg dropped slightly after that. Run some techron cleaner through it, and take it on a long drive. Get that carbon out the engine. This will help things drasticly. Techron is good for gas treatment carbon issues. Seafoam is good through the plenum, as it is most effective that way, but it will help through the gas tank. Let me know how things work out!

**BTW. you could STILL have a code without the CE light on!!!**

[msggunny]

Originally Posted by LANDY96

I think it will have some affect, but it shouldn't be that dramatic. I am on my 2nd 5-speed disco. First one was a stock SE7 with 255/70/16 tires(bigger than stock). I got 13-14 with city driving, and 17-19/20 on the highway. That is going 67-70 mph. No lead foot here people! The second one is a 96 as well, with a 4inch lift. 32" tires. I get @12.5-13 combo driving. I havn't checked it on the highway, but with a full rack I got about the same at around 65mph. I have noticed that O2 sensors on there way out will kill your gas milage too. I had a check engine light come on, and then turn off later. The stored code was an O2 sensor problem. Mpg dropped slightly after that. Run some techron cleaner through it, and take it on a long drive. Get that carbon out the engine. This will help things drasticly. Techron is good for gas treatment carbon issues. Seafoam is good through the plenum, as it is most effective that way, but it will help through the gas tank. Let me know how things work out!

**BTW. you could STILL have a code without the CE light on!!!**

Thanks, i am going to take it to get read tomorrow!

[Disco Mike]

Go ride with your wife and teach here how to drive a 5000 pound truck. No more 10 minute warm up, start and go only. What octane gas is she using, if she went to regular, you'll loose 2 MPG plus whatever her heavy foot may be taking away.
Don't waist your time over codes, no light, no codes.
Good luck,
Mike

[msggunny]

Originally Posted by Disco Mike

Go ride with your wife and teach here how to drive a 5000 pound truck. No more 10 minute warm up, start and go only. What octane gas is she using, if she went to regular, you'll loose 2 MPG plus whatever her heavy foot may be taking away.
Don't waist your time over codes, no light, no codes.
Good luck,
Mike

She drives it well, she is used to driving 100 and 70 series Land Cruisers in Zimbabwe.

The truck has had preimum in it for the past several months, but it didnt do any better for MPG than when i was running 87 in it.

Its free to check the codes, plus i want to see how its done so when i buy my own code reader i shouldnt have a problem.

I told her that she needs to stop with the 10min warm up crap. Bundle up if its that cold. Shit, i drive my SIII with no heater in this weather.

[Crysyn]

You know that idea of running techron through it and taking it for a long drive might work. No check engine light on mine, but noticed with the really cold weather and short trips I had been doing worse in MPG than expected as of late. Yesterday before making a five hour(each way) trip to Sun Valley, I thought maybe all the cold starts were making for a bit of carbon build up so I dumped some Lucas in the tank before heading up. I got 16.5 MPG on the way up and 18.5 on the way back, all highway and pretty flat. I was really surprised at the difference in mileage on the way back.

[ensignderrickman]

to be honest my 95 seems to get crap for mpg if i let it idle much. Turns about 750 rpm. I get 13-15 usually