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Lean bank 1 & 2 Codes


Rudie Del Rude

Well-Known Member
Joined
Sep 20, 2007
Messages
75
Age
36
Vehicle Year
1997
Transmission
Automatic
My ranger's been giving me lean bank codes since i got it. I suspected the MAF sensor for some time. I'de clean it with some contact cleaner, and the light would shut off. After that stopped working, i bought a new one, and it didnt do anything. Still getting the same codes.

It idle's alright until it gets warm, then whenever im not hitting the gas my lights dim every 2 seconds because its about to die. Hell, half of the time im at stoplights my engines idling so weird the whole truck will be rocking.

Also, i filled my tank about a week ago and noticed im only getting 12 mpg now.

What else could be the causes? How should i go about finding the cause? Could my egr valve be the cause, if so, how should i go about cleaning it?
 
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well on my 97 ranger I had the the same codes and it was a gasket that tends to go bad. I believe it was the lower and upper intake gaskets. if you do a search it is a pretty popular problem. Dont bother with o2 sensors and all that junk, its a gasket problem. the lean code means it is getting more oxygen into the engine than it can compensate for.
 
well on my 97 ranger I had the the same codes and it was a gasket that tends to go bad. I believe it was the lower and upper intake gaskets. if you do a search it is a pretty popular problem. Dont bother with o2 sensors and all that junk, its a gasket problem. the lean code means it is getting more oxygen into the engine than it can compensate for.


I second the gaskets, had the problem and that solved it. There is even a tsb on it.
 
I just went through all this as well. Check for a vacuum leak first!!! My vacuum leak was the brake power booster, my vacuum guage was steady @ 17inhg and really did not show a leak, but the booster would leak down in a matter of seconds and sometimes minutes. Check to see if yours is doing the same, and remember, a leak is a leak no matter how big or small.
Are your codes 172 and 173? That is what mine was. Post here often if you need help. There are a lot of people here that can help you.

Also, I read a post on here ( I think it is in the Tech Library) about this with the gasket. Pull #5 plug, is there oil on it? If so, you have to pull the intake and reseal it.
That is about as far as I can go now, Post your ?'s, we will answer as fast as possible.

-=Reno=-
 
Both banks lean is a vacuum leak. Get a couple cans of carb & choke cleaner, and on a cold engine, start it, let the idle settle down, then spray some of the cleaner around the joints between the maf and the heads. Where there is a leak, the engine will suck in the cleaner, causing the rpm to come up a little bit. It is more than likely the intake manifold gasket (as others have stated), it is a common problem in the OHV.

And obviously don't hose the thing down or spray onto the exhaust manifolds, or keep spraying it when the engine is hot. Carb & choke cleaner is flammable.
 
I would say your o 2 sensors are bad. they will give you those codes and poor gas milage

Just how much are you willing to back that up with?

It's a wild guess and the odds are against both sensors being bad.

The ABSOLUTE FIRST THING to find out is, are the codes correct? Were the sensors (or any other part of their circuits) actually bad, they wouldn't be. Pull the spark plugs and find out.

The most likely fault here is either a vacuum leak or an electrical fault such as poor grounding. But ANYONE who tells you they know what to replace after only reporting powertrain codes doesn't know what they are doing.
 
Here is my two cents. I have had those codes come up a few times, I have replaced the fuel filter and that always seems to fix it about 25,000 miles later I have to repeat the process
Hope that helps
 
Yeah, actually i'm going to replace my fuel filter first, and see if that does anything. Lately i can smell fuel between the cab and the bed when the trucks running.

I'm still waiting to check my manifold for leaks. I heard propane works too, as opposed to carb cleaner. That would be cool because i have some propane torches, and no carb cleaner. I'm waiting till i get paid.
 
"I heard propane works too, as opposed to carb cleaner"

:icon_surprised: :icon_surprised: :icon_surprised:
:scare: :scare:

You trying to burn your truck down, and if close enough to your home, your home? Use a Spray bottle (like an old windex bottle) and fill it with water, then spray your intake and vacuum lines as much as you like. The engine will bog down when you hit the sweet spot.
 
Been a while but heres an update.
I pulled the spark plugs off and looked for anything out of the ordinary but they were normally worn, just excessively. After i changed those the truck runs much better. It still bogs down every now and then and the gas mileage still isnt where it should be, I'm thinking about a new EGR valve for that. I dont think the codes ever came back. However my wirings a little weird in the dash, i used to be able to hit my dash and it come on, but it hasnt come on when the trucks running like it used to shortly after i changed the plugs.
 
Dude, it's almost sure to be a vacuum leak, it's very common for these.
 
I've wasted about 3 cans of carb cleaner looking for a vacuum leak, even pulled off all my vacuum lines to see if they were dirty and they were clean as a whistle.
 

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