I got the two codes recently. They show "System Adaptive Fuel Too Lean (Bank 1 and 2)". I asked for help troubleshooting on this board. The advice I got was to remove and clean the MAF sensor and clear the codes. If that didn't work, check for vacuum leaks.

I removed and cleaned the MAF, although it looked pretty clean. I used some electrical component cleaner on the resistance wires, and cleaned everything else. I also checked all connections I could think of in the air intake system. Everything was pretty tight.

I reset the codes, and drove about a week (250 miles). Today they reappeared.

I checked for vacuum leaks and I could not find any. I put a gauge on the vacuum, and it showed 20 1/2 inches at idle, with the needle very steady. Looks to me like the vacuum system is OK.

Any suggestions from here? Driveability is fine. I can't notice anything different except that the check engine light is on. No problems at idle, accelerating or at high/low speed driving.

Thanks!

 

Leaking intake gaskets usually show up on these only when the engine is cold.
If you check for vacuum leaks right after firing it up cold you may have better luck. Usually you only have a couple minutes after firing it up to check.
I use Carb-Medic spray carb cleaner for checking. Just spray it around the lower intake manifold and listen for any change in idle speed.

 

When these two codes show up simultaneously, they're usually caused by leaking intake gaskets. They're actually O-rings that separate the upper portion of the intake from the lower. The gaskets get hard and brittle with age, and lose their seal. It's not a hard job to replace the gaskets, just have to remove some stuff to get to them.

 

Those codes were corrected by replacing intake manifold gaskets on my '96 Explorer. It used a gasket rather than the O-ring style on the newer Explorers.

 

Also look for any un-meetered air leaks. These would be things like a unproperly seated air filter housing, crack in the air intake tube AFTER the MAF, unplugged vacuum line into the air intake tube ect... Because BOTH banks are indicating lean, you need to look at things that can effect both. Intake manifold gaskets can be one source.

 

Thanks. I'll try all the troubleshooting suggestions, and replace the intake manifold gasket if that's what is wrong, or if I can't find anything else causing the problem.

It's a '98 Explorer Sport with about 130K miles on it, so I can see where the intake manifold gasket may be the problem.

Are there any problems with driving for the next couple of weeks with this condition? Valve damage?

 

I am pretty sure you will find that you have a vacuum leak. It is a very common code for Fords in general. In the Sport and Sport Trac era it is the elbow that goes into the near the front of the on the passengers side.

If you were to follow the the line/elbow back you would find it is attached to the PCV.

The hose cracks on the bottom so you normally have to pull it off to see the crack.

 

This is good to know yet most frustrating. I've had my truck to the dealer 3 times for a 'rattle' that seemed to be coming from the left converter. At first they put some clamps on the heat shield which ended up doing nothing. They then told me that it 'might' be coming from within the catalytic converter. Due to the fact that there was originally no 'service light' on they would not replace this under the 80k warranty. Well, my light just came on and it has spit out these 2 codes. I have 79,600 miles and will be taking it back to the dealer tomorrow. Do I have any ammo on this? I'm almost convinced they will find a way to replace an O2 sensor and not replace the cat like i 'believe' they should. The rattling has been making us insane!

 

If the 2 codes you are refering to are P0171 and P0174 for engine lean are what set the check engine light and you are going to go to the dealer looking for a new cat then good luck with that. Those codes have nothing to do with the cat. Those codes are brought about by dirty MAF and/or vaccuum leaks for the most part.

 

Please don't get me wrong. I'm not looking for a new cat per se. There has been an internal rattle (only in gear) for some time and has progressively gotten worse. I believe that this is defective and is now causing emission failure to a certain extent. The dealer told me I had little recourse as I did not have a 'svc engine light on'. Now that i have the light at 79,600 miles, they will most likely deny me again. WTF? My biggest fear is that I pass the 80k point, I then go to get my emissions done, I fail, then the only true fix is to replace the cat. This is one of the major components covered under that federal warranty. Once I pass 80k, i will be out of. I've gone so far to call the epa to see what other options I may have. The rattle is most annoying, granted, but I really only prefer to be sexually assaulted by my wife. I hope this makes sense and I really don't think my requests and/or demands are unreasonable.

 

Welcome to the forum route2null0

I believe that you will only have emissions warranty, which would cover the catalytic converter, if it failed and caused the the truck to fail emission testing, or if the Check Engine light was on because of it.
Like 73f100 said the codes you got aren't due to a catalytic converter problem.
Unfortunately if you want to cure the rattle you'll probably have to pay for a new converter

 

Yah... I called the EPA guy again. Looks like the only way this is going to get covered is if it spits out a 0420 code... I'm screwed. I sincerely appreciate everyone's information, even though I really still feel that the dealer should fix a broken cat.. being that it's a major emissions component. But wtf do i know?

 

My wife's 99 Explorer had the same codes. Solved it by cleaning the MAF and Throttle Body (which was filthy). Hopefully, the light stays off. I don't think the intake manifold gaskets where the problem with her Explorer as it started and ran fine when cold, but stalled on warm start.

 

> The rattle is most annoying

If this is really coming from the converter then most likely what has happened is the blanket (ceramic?) that surrounds the core to protect it from thermal shock (ex: driving through a puddle while hot) has shifted or was not installed correctly. Which you should have noticed since the vehicle was new.

So, it is rubbing and bouncing around inside the converter shell driving you crazy and wearing down. Many times when this happens you can see the dust inside the tail pipe.

You should really take this up with a zone rep, go for the ride, and ask him if this is "job one".

That is assuming you are the original new owner. From the sounds of it, you bought it used and are taking it back to the dealer to have a part replaced under warrranty when you did not buy the vehicle there?

 

No, I am he original owner. To be honest I believe the rattle has been there for a long time, but my wife is the primary driver. It has progressively gotten worse from what it seems.
I asked the dealer to type up and sign a piece of paper stating they were trying to sell me 2 new catalytic converters (which they were) but the would not do that. That smells funny to me. The codes were actaully from a leak in the intake manifold along with the maf. I had my regular mechanic fix this as it saved me about 300 bones..
I told this particular Ford dealer to kiss my a&& and they would never see me purchasing anything from them. At the current moment I am about 150 miles shy of the 80k...