Worst gas mileage

Vinny
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Joined: Fri May 27, 2011 9:47 am

Worst gas mileage

Post by Vinny » Mon Nov 26, 2018 9:41 am

Hello all,
Trex has 60000 miles (91000kms) and I have just installed new Motorcraft spark plugs and PCV valve and now my gas mileage is worse. I was using 12L/100km (20 mi/gal) and now I'm using 15L/100km (15.5 mi/gal). What happened!!?
2008 TREX LTD Silver Birch
4th Trex since 2011
Bought July 2018 91000km


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CARR142
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Location: CHERRY HILL, NEW JERSEY
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Re: Worst gas mileage

Post by CARR142 » Mon Nov 26, 2018 2:09 pm

Vinny,
Did you disconnect the battery doing this spark plug install?
If so PCM needs to relearn it's paramerters.
Hope this helps.

Vinny
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Posts: 89
Joined: Fri May 27, 2011 9:47 am

Re: Worst gas mileage

Post by Vinny » Mon Nov 26, 2018 2:43 pm

Thanks, no, I didn't but I have since then, disconnected it and still no change. Was watching a video and the mechanic suggested disconnecting battery, and then use a wire to the positive terminal and to the disconnected negative clamp to 'drain' all the memory from the capacitors in the PCM. Then after about 5 minutes, reconnect and heat engine to normal running temp. Shut engine off, disconnect electrical connection to the Throttle body and remove body to clean it. Also clean the throttle sensor.

I don't know if all that will help but gonna try the very first time the temp outside gets to 40 degrees again.
2008 TREX LTD Silver Birch
4th Trex since 2011
Bought July 2018 91000km

spy1309
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Joined: Mon Jun 23, 2014 12:51 pm

Re: Worst gas mileage

Post by spy1309 » Fri Nov 30, 2018 9:10 am

In colder weather you will get worse mileage , also the gas gets reformulated for winter ...as a test try a tank of premium gas from Shell with no ethanol...if the mileage improves you have and answer if not .....you do have a problem.

Vinny
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Posts: 89
Joined: Fri May 27, 2011 9:47 am

Re: Worst gas mileage

Post by Vinny » Fri Nov 30, 2018 9:37 am

Thank you CARR142 and spy1309. I will try the premium gas routine and let you know.
2008 TREX LTD Silver Birch
4th Trex since 2011
Bought July 2018 91000km

pwschuh
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Posts: 296
Joined: Fri Nov 26, 2010 9:09 am
Location: Mid-Atlantic

Re: Worst gas mileage

Post by pwschuh » Sat Dec 01, 2018 5:10 am

The worst mileage I ever got was the time I started the T-Rex one evening to check something on the engine, went into the house, got distracted and never came back out to finish. Went out the next morning and it was still idling happily. :oops:
2008 TX Limited
Silver Birch Metallic/Black leather
WeatherTech floormats all rows
Bought used on 17 Nov 10 with 20,000 miles

Vinny
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Posts: 89
Joined: Fri May 27, 2011 9:47 am

Re: Worst gas mileage

Post by Vinny » Sat Dec 01, 2018 9:00 am

Hope it was a 'pleasant distraction'!
2008 TREX LTD Silver Birch
4th Trex since 2011
Bought July 2018 91000km

jayb1976
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Joined: Sun Dec 02, 2018 3:49 pm

Re: Worst gas mileage

Post by jayb1976 » Sun Dec 02, 2018 3:56 pm

I just changed the throttle body (this is my third one bought a carid remanufactured one) worked for 1 week just like the previous ones (original ford ones second but tested ones) and now have the same problem again, but here is the relearn process for the PCM I used it for myself after changing the throttle body had to make the re-learn process.
RELEARN process:

Here is the link https://www.youtube.com/watch?v=ZNxXM75zJOw&app=desktop.

I have a heated throttle body I think the only thing I can do and my last chance to change to a non heated one hope this will resolve the issue, I am fighting this for nearly 2 years a lot of energy for an old car.

Vinny
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Posts: 89
Joined: Fri May 27, 2011 9:47 am

Re: Worst gas mileage

Post by Vinny » Sun Dec 02, 2018 6:29 pm

Hi jayb1976,
Maybe you should try starting a new topic so more guys will focus in on your problem.

good luck.
2008 TREX LTD Silver Birch
4th Trex since 2011
Bought July 2018 91000km

jayb1976
New Member
Posts: 2
Joined: Sun Dec 02, 2018 3:49 pm

Throttle Body HELPPPPPPP Please

Post by jayb1976 » Sun Dec 02, 2018 7:15 pm

After we rebuilt the tranny and spent a fortune cause the car had only 96.000 and in good shape, we found out that the throttle body can have some issues.Went to Ford with the documentation for throttle body recalls ( they rejected me explaining that the recall warranty etc was already expired for 2 weeks, that was last year). Quoted me $850 for changing it.Next step we cleaned it in the shop which lasted for another 6 months and was running after that same issue.I bought a refurbished tested one from ebay which lasted 1 week.Luckily the company refunded my money after sending it back, ordered a remanufactured one from carid ( https://www.carid.com/cardone/throttle- ... -FEALw_wcB ), issue is the same after 1 week.
I did everything as needs to be done disconnected everything, cleared the PCM, and did the re-learn process after installing the new one.This is a heated throttle body and ordered the same one the car was running very well, tested but any time the weather is getting cold below 40 degrees the issue start all over.Last error code I dah was P0701 but after changing the body, cleaned the codes was running perfectly, I am just disparate about this whole situation.
Please HELPPPPP if you now what should i do, or you have any thoughts.

pwschuh
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Posts: 296
Joined: Fri Nov 26, 2010 9:09 am
Location: Mid-Atlantic

Re: Worst gas mileage

Post by pwschuh » Mon Dec 03, 2018 3:59 am

You didn't start a new thread. You just posted the same thing in the same thread. Go back out to the main Taurus X forum page and click the red "New Topic" button near the top left.
2008 TX Limited
Silver Birch Metallic/Black leather
WeatherTech floormats all rows
Bought used on 17 Nov 10 with 20,000 miles

Vinny
Regular Member
Posts: 89
Joined: Fri May 27, 2011 9:47 am

Re: Worst gas mileage

Post by Vinny » Thu Dec 06, 2018 10:23 pm

spy1309 wrote:
Fri Nov 30, 2018 9:10 am
In colder weather you will get worse mileage , also the gas gets reformulated for winter ...as a test try a tank of premium gas from Shell with no ethanol...if the mileage improves you have and answer if not .....you do have a problem.
Well I think cleaning the throttle body and then resetting the PCM as listed previously here, the mileage has gone from 15L/100km to 13L/100km. Then later in the week I did use Shell premium gas but no change noticed in mileage.
2008 TREX LTD Silver Birch
4th Trex since 2011
Bought July 2018 91000km

Vinny
Regular Member
Posts: 89
Joined: Fri May 27, 2011 9:47 am

Re: Worst gas mileage

Post by Vinny » Mon Dec 10, 2018 4:11 pm

Ok, how bout this folks, for all the Trex owners in the upper Midwest and Canada, how many Litres per 100 km are you using in these cold temps of 0 Celsius or 25 F ? I'm back to 15kmL/100km which I think is a little high.
2008 TREX LTD Silver Birch
4th Trex since 2011
Bought July 2018 91000km

scudrunner
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Posts: 5
Joined: Mon Sep 06, 2010 9:32 am

Re: Worst gas mileage

Post by scudrunner » Mon Dec 10, 2018 7:48 pm

Just a guess but if you replaced the plugs and didn't get a good seal on the intake manifolds gaskets for the rear plug it could effect your mileage although it should cause a "leaner" mixture. I think that would trigger a code also so as I say its just a guess.

Ryan57us
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Re: Worst gas mileage

Post by Ryan57us » Tue Dec 11, 2018 7:54 am

I'm getting about 18-19 mpg city and 23 max on the highway. I'm not sure if this is bad, decent, or good.

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