PO172 just won't go away!

About 2.5 months ago i got the P0172 code, bank 1 system too rich. So i replaced the air filter and cleaned the MAF sensor with the special cleaner spray. Everything seemed fine, then last week the code popped again. I cleared it and then after a few days of driving back and forth to work it popped again. I checked the air filter and it didn't seem clogged or even really dirty. why would it be fine after 2.5 months and then start up again? do the filters typically need to get replaced that often? I can't believe it's that sensitive....

I assume the next thing is cleaning the throttle body?

 

leaking injectors? How many miles?

 

160k miles, got it last yr with 146k on it, but the previous owner claimed it had been dingy towed behind an RV for 86k miles, so only 60k on the engine...but it could also actually have 160k on it, who knows.....

leaking injectors? How would I know that?

 

The most common is when you go to start the motor after it's been sitting for only 30 minutes after you used it last. You get long cranks before it will start.

Essentially, the engine is flooded because the injectors leaked raw fuel into the intake.

If you have hard, hot starts, you most likely have leaky injectors.

 

Yes! It has also been starting hard when the engine is hot! Huh....

I just watched a youtube on fuel injector replacement, looks a little too complicated for me to want to attempt....any guess on how much that would cost to have a shop do? i see the parts are bout $80-$100

 

I don't know what rates in your area run. I allow things to be a bit more expensive because you never really know if something unintentional will break on our older trucks.

If you got quoted around $300, I'd say go for it.

 

Yup, pretty sure koditten is right. There was a long saga on another 1st gen a year or so ago (maybe longer) that turned out to be a leaking injector, similar symptoms. I'm not sure how they would isolate it to a single injector without pulling them all out and running a test. $300 would probably be a good deal.

 

ok thx guys...i just put 550 into the truck for shocks...i may wait on the injectors for now

 

Going by memory here, but I think it was @mechanicjon that found his bad injector(s) by inserting a piece of paper into the spark plug hole and seeing gas drop on the paper...I think.

For that matter, I have leaking injector(s) as well. I just seldom get in the truck after a short duration shut down. Its always 12 hrs in between starts so I don't notice it.

 

At that point it's just starter fluid.

 

Another cause of a P172 code is a bad O2 sensor. The one before the cat could trip this code. Take a look at that.

 

update on my P0172 code: so i cleaned the MAF today. I've never cleaned one before so i looked it up on the internet, found a video that showed removing the sensor and cleaning it with the spray, ensuring to spray both the outer sires and inside the unit where the inner wires are. When i examined it right after taking it out, I noticed the inner wires weren't clean, they were actually filthy. this is significant because i asked my mechanic 2.5 months ago to clean it when he was replacing the ball joints. i bet he simply pulled the air filter out and stuck the spray can in the inlet and sprayed the sensor without removing, cleaning the outer wires but not the inner ones. would this have made the computer show a p0172? i figured that basically he did a half ass clean and thats why the code popped again. or, like you guys have said, maybe its a leaky injector, hope not though...

 

Could be a leaky injector, could be the O2 sensor, or could be the dirty MAF. If the MAF was that dirty, you might want to pull your negative battery cable for several minutes to reset things (if you haven't already).