oxygen sensors show LEAN on Explorer

[Mike Heatley]

car specs below...

-- had this in to a mechanic three times on same issue
-- oxygen sensors showing I'm running lean on fuel mix, causes engine light to come on
-- a symptom of leakage due to gasket deterioration, I'm told
-- mechanic uses propane flame to detect any leakage, none found
-- symptoms 6 months apart
-- runs fine, no problems with stalling out, rough idling, etc.
-- mechanic shows two technical service bulletins issued on this symptom
-- car specs: 97 ford explorer, 52K miles, 6 cyl, warranty expired so didn't see the point in taking to a dealer & turning over big wads of cash to get the same answer

grateful for any hints on this puzzle

 

[steve_burton]

hi Mike.
i just had both o2 sensors replaced.
1st engine stalling
2nd engine light came on, 1st told manafold gasket so replaced that, that enigine light came on again so 2nd o2 sensor repleaced! now running great and better MPG.
all up cost aud$850 / usd$400.
Cheers Steve.

 

[Robert]

If your '97 is a SOHC, leaking lower intake manifold o-rings cause your engine to run lean. Ford extended the warranty on them to 6 years, 72K miles. Since you are below that it might pay to take it to Ford to let them repalce them for free if they can confirm that leaking o-rings are the problem.

 

[SWLathrop]

And push the issue (not nasty like though) with the gaskets. We have replaced several that tested OK for "NO LEAKAGE" that actually cured different drivability issues when replaced. Mainly because they leaked under different temps and vaccumm levels. And when looking at the old ones, you could actually see where they were leaking.

 

[expl0der8]

I have just went through this myself on my 98 X. It was running real rough when it was cold, but ran fine once warm. Took it to a dealer and they said the MAF was bad and the upper/lower intake gaskets were leaking. Took it to another shop and they said there were no problems. Ended up driving it for another week before saying the hell with it and got it all replaces. I don't think the MAF had much to do with it, but it was definately the gaskets. Now it's like a brand new truck. Whish i had knowen about the extended warranty, but i don't know if it would also be on the 98

 

[Robert]

The extended warranty on the manifold o-rings covers all SOHC Explorers for 6 years, 72K miles that were built through 4/7/00. Since the SOHC hasn't been out for 6 years yet, as long as you had less than 72K miles, it would be covered. Unfortunately, Ford will only reimburse you for customer paid repairs if they were made before the date on the letter which was 12/00.