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Author Topic: Sudden drop in fuel economy...  (Read 4537 times)

Kev93

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    • '93 XR2 | Ford F-150
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Sudden drop in fuel economy...
« on: December 03, 2012, 06:04:00 PM »
Since November last year my '93 XR2 has been averaging around 28MPG as my daily ride to work.

I've had it in the shop recently for 5th swap and had new tires at the same time.  They also replaced the speedometer cable, which was scratching like a rap DJ.  My last 3 tanks have been 22MPG, 23 MPG, and 25MPG after the new 5th gear was installed.

About the only real "change" I know that coincides with this is bolting on the hard top early in October (which was about 3 tanks ago due to the shop time).

I'm sure there might be several possible causes for the drop in economy.  Can anyone give this tech-challenged old man some things to check before I send her *back* to the shop?

Thanks!
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/* Just along for the ride */
\\\'93 XR2 in progress | Daily Driver | 5th Gear Swap | Rocketman VAF Adapter

Kev93

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    • '93 XR2 | Ford F-150
    • http://ombe.com
Sudden drop in fuel economy...
« Reply #1 on: December 06, 2012, 10:34:00 AM »
Next tank was also @25MPG.

So, I'm getting the extra 3MPG from the 5th gear swap, but I had a drop of @6MPG two tanks before it went in the shop.

Injectors need cleaning?  I took a brief look for disconnected vac hoses at lunch today.  Any thoughts?
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/* Just along for the ride */
\\\'93 XR2 in progress | Daily Driver | 5th Gear Swap | Rocketman VAF Adapter

tonlaw71

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    • 1992 XR2 and a 2013 Nissan Juke
Sudden drop in fuel economy...
« Reply #2 on: December 06, 2012, 01:15:00 PM »
I think you might be on the right track with the dirty injectors. Toss a can of B-12 Chemtool into the tank. You may have to do it for a couple fill ups, but it does wonders to clean the fuel system. Run 2 cans through it, then change the fuel filter. It always worked for me...
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///Tony aka Bubba Gumpshrimp\\\

///'92 Plasti-Dipped XR2\\\

azgtx

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Sudden drop in fuel economy...
« Reply #3 on: December 06, 2012, 02:17:00 PM »
Check the wire and connector to the o2 sensor. If there is an issue with it it will push the ECU into open loop (wide open throttle).
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