Whatcha Think?

[NWwoman]

Ford Explorer 2000 125,000 miles / well-maintained

* Six months ago noticed hesitations occurring when accelerating from start but not always and not often
* Started noticing a slow decline in mileage per gallon. It had run at 19-21. Was creeping down to 18, then 17, then 16
* Three weeks ago, CEL came on. Shop read codes: both banks/running lean/oxygen sensor
* Shop checked for leaks/found none. Told me to come back if CEL came back on
* Freaked when last night I did a 8 mile roundtrip on gravel and saw mileage per gallon is now fluctuating between 13.5 and 13.6.
* CEL is not on.

Why would it be consuming so much gas if it's running lean?

Whatcha think? Anything easy I can do or should know before taking it to shop?

Female (widow) here and I only do easy things on Explorer but like being in the know before I hand the keys over to shop.

Is it safe to drive to shop???

Thanks!!!!

 

[deweyville65]

Irregardless of what your shop says, I would tend to think the intake gaskets are leaking, or a bad PVC valve hose leaking. Something is causing a lean condition to be seen by the O2 sensors which tell the computer to richen the mixture, causing your declining fuel economy.

 

[koda2000]

Irregardless of what your shop says, I would tend to think the intake gaskets are leaking, or a bad PVC valve hose leaking. Something is causing a lean condition to be seen by the O2 sensors which tell the computer to richen the mixture, causing your declining fuel economy.

yep. you've got a vacuum leak somewhere. all engines create vacuum when they're running. this vacuum is used to operate various controls on the vehicle (like your power brake booster, HVAC controls, crankcase ventilation). as the codes indicate lean on both banks, un-monitored air is getting sucked into the engine. as the computer doesn't see it going through the vehicle's mass-air-flow (MAF) sensor it doesn't add enough fuel to optimize combustion. your vacuum leak may originate from any of the following places:

- fuel vapor evaporation system
- intake manifold gasket leaks
- cracked/disconnected vacuum lines
- faulty power brake booster
- faulty HVAC controls
- cracked PCV valve hoses, elbow or loose grommet
- cracked intake duct after the MAF sensor

a good mechanic will have to check all these things. i suggest you try a better mechanic. a good way to find leaks is to introduce smoke under pressure into the intake. better mechanics have these tools.

 

[NWwoman]

Well...well...well.... a local farm guy stopped by unexpectedly and I grabbed him to take a look.

Dig this -- appears that the guy who replaced my air filter failed to place it correctly, so it was tipped up (grr) and letting carbon in, which has coated the MAF.

Why are some people so sloppy? Grrrr.

 

[Turdle]

We'll have you wrenching on your own truck in no time.

http://www.explorerforum.com/forums/showthread.php?t=393139&highlight=maf+cleaning

Book mark this one

http://www.explorerforum.com/forums/showthread.php?t=386329

And this

http://www.explorerforum.com/forums/forumdisplay.php?f=113

Second link has this thread in it-which you need right now.

http://www.explorerforum.com/forums/showthread.php?t=154711


Everything you could encounter has been, and most of it has been documented here. You are in the right place.

 

[NWwoman]

Cool! Thank you very much..... Still thinking the horse is a whole lot easier though...

We'll have you wrenching on your own truck in no time.

http://www.explorerforum.com/forums/showthread.php?t=393139&highlight=maf+cleaning

Book mark this one

http://www.explorerforum.com/forums/showthread.php?t=386329

And this

http://www.explorerforum.com/forums/forumdisplay.php?f=113

Second link has this thread in it-which you need right now.

http://www.explorerforum.com/forums/showthread.php?t=154711


Everything you could encounter has been, and most of it has been documented here. You are in the right place.