8 Mpg?

[alpinestar]

well thanks for a whole lot of nothing. there IS something wrong. today it started cutting out very quickly again. it sounds like a subaru now cuz its constantly cutting out. its much faster than before when it was just the plug wire.... i know im not getting anywhere near 20mpg and its not my how im reading it. ive filled up 100% before and never got anymore than 170 miles to get right back to where i was which was empty. and my gearing is stock with 31 inch tires which does make a small difference, thats why i said 8 and not 6... lol

 

[Jspafford]

If you snap at people don't expect them to be willing to help.

Good luck.....

 

[b2rich]

i was getting 11 and 12. a couple of weeks ago i changed the atf and filter with a flush. also did a oil change and switched to castrol edge. I just got back from crescent city via the coast. averaged 17.3 down and 19.7 back

Im running 235s and 3:73s

 

[CraigK]

Yesterday at 1:32 you reported you put in a new O2 sensor, but hadn't checked it yet. Then at 2:19 you indicate it is constantly "cutting out". Is this after the O2 change?

You can EASILY get 8 mpg with a 2.9 with a bad O2 sensor (been there), typically accompanied by "cutting out" or bogging, but I would have thought things would have improved considerably with the new sensor.

Any mileage/performance change with the new sensor?

CraigK

 

[holyford86]

I'm surprised no one said it yet... PULL CODES

 

[88gt]

DUDE, you have the same problem i had, just replace the battery cables!!! corroded cables will send less power for the fuel to burn and the engine will compensate for the lack of spark with more fuel. as the cables heat up from all the interference, the power becomes unconstant and causes the engine to cut out. Try the battery cables, its a 12 dollar fix and will bring the power and mpgs back up!!

 

[bluebombersfan]

First of all do you have a CEL light on?

I'm no mechanic but changing an 02 senser is just a guess. Do you have a CEL light on? I believe your truck is obd 1, it will tell you if you need an o2 sensor if it is.
It is true that the older non heated type of o2 sensors that is in your truck would foul up pretty easy but that should set off you CEL light on if that is the case.

 

[Cyberbeer]

22.4!!!! Is it 4x4. I can only get 19-20, shifts always at 3k. Course mines a super cab

 

[Kona]

I am getting 17.5 US mpg in a 4400 lb 91 supercab with 3.73's and 33's ( yes , uphill at highway speed sucks a**) of course I have a 4.0 so........

 

[btank]

22.4!!!! Is it 4x4. I can only get 19-20, shifts always at 3k. Course mines a super cab

im only getting about 16 mpg out of mine, i've never heard of one getting over 22

 

[Hahnsb2]

im only getting about 16 mpg out of mine, i've never heard of one getting over 22

I got 23MPG on the freeway once out of my old 2.9...

 

[holyford86]

I'm consistently getting 18-19 mpg out of my 2.9 I'm running 4.10 gears, 33 inch tires and 6 inches of lift, as well as being converted to MAF. At one point I was getting about 9 mpg with my old motor running terribly, it was a combination of a few things, bad o2 sensor, vacuum leaks, and an incorrectly adjusted tps, along with some messed up wiring.

 

[RustedRanger]

When you put in new parts that may help it run better always unhook the battery for awhile. I had a friend do a diagnostics check and found a couple problems and fixed them and it seemed to run a little better. After a few days of driving it seemed to not get any better so since the vacume was kinda low I put some Restore in the oil and some Lucas fuel treatment and filled it up......it started running worse! Well I unhooked the battery last Sunday night and hooked it back up on Monday and took it for a drive, it made a big difference! It doesnt run perfect but it runs way better that it did.

 

[JTH1972]

Its the one sensor that should be replaced every 50K as a tune up piece. They degrade.

really? That often eh? looks like I'll be shopping for one! Is there only one in the 2.9? Any way of testing the cat to see if it's plugged?

Test your coolant temp sensor first. Known problem on the 2.9.

I've seen a couple of sensors on the manifold that I assume are for the coolant. Which one is it exactly?

Sorry to hijack the thread. Looking to solve a couple problems on mine too!

 

[Bondo]

The coolant temp sensor is on the top left front of the engine. (the bigger one)