5.3 PO171 engine code (lean) bank 1&2

[Wildfowler]

Does anyone here know how fuel injectors and the computer that controls them works?

Does the computer that controls the fuel injectors make its calculations based on full operating fuel pressure? Or does the computer make calculations based on the fuel pressure reading at a continuous point in time?

Can a weak fuel pump cause a lean error code? I'm assuming the answer is yes but don't know.

I am getting the lean engine code I think the number is 171, intermittently. Check engine light will come on for a few days then it will go off for a few days. I've got an inexpensive code reader and it's the same code every time.

When the engine code decides to come on, my engone idle becomes rough. It's never stalled out and never gets to the point where I think it's going to stall out, it just idles rough. I also get hesitation and sluggish acceleration. Highway operation seems normal. And fuel economy actually seems a little better lately.

Previously, I was getting misfire cylinder one and systematically changed everything on cylinder one.

I'm sure I could benefit by having the throttle body physically cleaned, but I don't know that a dirty throttlebody would cause intermittent rough idle?

I know it's not duckhunting related, but does anyone have any thoughts on this? I don't see any point in me joining a Chevrolet or GMC truck forum since someone here probably knows about this?

Thanks.

[donia]

I'm sure I could benefit by having the throttle body physically cleaned, but I don't know that a dirty throttlebody would cause intermittent rough idle?

it did on my '01 Yukon with 5.3. the carbon build up along the lip would cause the throttle to not seal completely at idle. once cleaned, rough idle settled out (rough idle was usually my indicator to clean it).

if you don't have it removed and cleaned professionaly, you can take some throttle body cleaner in a can and hold the butterfly open, spray inside good and let it sit for 5 mins or so. then take a clean rag and wipe as far back as you can (screwdriver inside rag as a prod helps). you'll have to spray and wait a few times if you've never cleaned it previously.
some cleaners get to perform this while the truck is cranked, but it is near impossible without a helper feathering the throttle to keep truck cranked once you remove the breather hose from the front of the throttle body. if you are going that route, you'll spray into the throat of the throttle body until it chokes the truck out, leave it off for 15 mins or so and then crank it and run it until the smoke clears (like seafoam through the vac-hose).

[Wildfowler]

There is a video on seafoam website that shows you how to use their throttlebody cleaning product. But I think they want you to go snake a tube through the air breather at the air filter location?

If the throttle body is not sealing off correctly I suppose it could be allowing more oxygen to enter the system which would cause a lean reading? Is that even possible?

A helper would be mandatory since there's no throttle cable anymore!

[donia]

http://seafoamsales.com/wp-content/uplo ... Intake.pdf

ahhh, the bended tube/guide is so you can put the intake hose back on... so the truck will run while you spray the seafoam into the throttle body (still need a helper or a brick to keep throttle at 1000rpm above idle while spraying). loosen the clamp on the hose where it attaches to the throttle body and remove it to put the tube guide on then replace the hose, not between the mass air flow sensor and throttle body (don't spray any through the mass air flow sensor from the filter box side).

[jacksbuddy]

I got the exact same code on my '05 Escape V6. I ran some higher grade gas through it once, and that helped. Then I ran some Chevron gas in it, and that seemed to clean it up. It was either that or get a new Fuel Rail Pressure Sensor. Changing that out is very straight forward, but so is the price. Running higher quality fuel for a tank or two is a LOT less expensive.

[deltadukman]

might be too late but I did that seafoam throttle bottle clean out thing once on an 05 Chevy and the truck smoked ever since. We're talking an 80k mile truck. Its like it burned the rings or some seals up. Never again for me.

[Wildfowler]

might be too late but I did that seafoam throttle bottle clean out thing once on an 05 Chevy and the truck smoked ever since. We're talking an 80k mile truck. Its like it burned the rings or some seals up. Never again for me.

Really? I haven't done mine yet. Probably going to just remove throttle body and clean by hand anyway.

I'm just a little worried about the throttle position "re-learn" period.

As it is now, my light comes and goes so I'm not terribly worriedly about it.

Thanks.