Engine vacuum, P0171 and P0174 codes.

[foxtrot moon]

Ya'll must wear some tight skirts with this ***** session going on. Waste of space, horrible forum if people want to close a thread out with posts criticizing the OP. God forbid I forgot to list a symptom that had only happened once.

 

[OR VietVet]

Ya'll must wear some tight skirts with this ***** session going on. Waste of space, horrible forum if people want to close a thread out with posts criticizing the OP. God forbid I forgot to list a symptom that had only happened once.

Ya'll will not have to worry about it because I will memorize your name and not respond so you will not have to worry about being detailed in "your" request for help. Whether the symptom happened once or multiple times it can be important to the final outcome but heck, I am telling you something that won't mean anything because you decide what is important to share and not us. Have fun throwing parts at your rig.

 

[H0E2]

Hello all!

While i am a "New" member i have been lurking in the shadow's reading about and learning alot of information about my Tahoe.

The reason i am posting in here is because i used forum search for my problem and while it is the same as the OP i have different symptoms. So rather then start a new thread thought i could just use this one since it is at the top of the search.

Details about my Tahoe:
2002 Tahoe LS Flex.
5.3L V8 4x4
Odometer Reading at time of post:180562

So since it started to get cold here in the Poconos i have noticed a problem developing. When at idle (When cold out under 45F) she seems to idle rough not as rough as a misfire but enough to feel it in the wheel.She does this at start-up and when warm.Truck is idling around 600-700 RPM
I have no acceleration problems no drive-ability problems either.
Couple of days ago the SES Light came on upon connecting the code reader i found the following:
P0171

Bank 1 System too lean.
P0171
Bank 2 System too lean.

I then cleared the codes and kept on my way.They stayed off for roughly twenty miles then returned.Upon searching around the forums i have noticed our IMG'S(Intake Manifold Gasket's) are of poor design and an updated version exists and that the IMG'S seem to be the safe bet on what my problem is.I have sprayed carb cleaner around the gaskets but i do not notice any change in idle.Could be i am not hitting the spot idk...

Now i plan on changing them tomorrow hopefully its very cold and i just welcomed my son into the world on Saturday so time needs to be well spent hence why i am here...Is the IMG's in your opinion the problem i am having?

Thank-You in advance and if i am wrong for posting this here please move it and correct me.

If you are wondering:
Greyson Maverick Rehm
01/03/15
0448
9Lbs 9oz

 

[SLCHOE]

Hello all!

While i am a "New" member i have been lurking in the shadow's reading about and learning alot of information about my Tahoe.

The reason i am posting in here is because i used forum search for my problem and while it is the same as the OP i have different symptoms. So rather then start a new thread thought i could just use this one since it is at the top of the search.

Details about my Tahoe:
2002 Tahoe LS Flex.
5.3L V8 4x4
Odometer Reading at time of post:180562

So since it started to get cold here in the Poconos i have noticed a problem developing. When at idle (When cold out under 45F) she seems to idle rough not as rough as a misfire but enough to feel it in the wheel.She does this at start-up and when warm.Truck is idling around 600-700 RPM
I have no acceleration problems no drive-ability problems either.
Couple of days ago the SES Light came on upon connecting the code reader i found the following:
P0171

Bank 1 System too lean.
P0171
Bank 2 System too lean.

I then cleared the codes and kept on my way.They stayed off for roughly twenty miles then returned.Upon searching around the forums i have noticed our IMG'S(Intake Manifold Gasket's) are of poor design and an updated version exists and that the IMG'S seem to be the safe bet on what my problem is.I have sprayed carb cleaner around the gaskets but i do not notice any change in idle.Could be i am not hitting the spot idk...

Now i plan on changing them tomorrow hopefully its very cold and i just welcomed my son into the world on Saturday so time needs to be well spent hence why i am here...Is the IMG's in your opinion the problem i am having?

Thank-You in advance and if i am wrong for posting this here please move it and correct me.

If you are wondering:
Greyson Maverick Rehm
01/03/15
0448
9Lbs 9oz

Not necessarily. That would work for a serious intake leak but more common is an intake leak that is smaller but large enough to dilute the air/fuel ratio to a lean condition enough to set those codes.

A better way to verify an intake leak is to do basically the same thing but with a scan tool that provides "live" (realtime) ECM data, specifically short-term fuel trim and long-term fuel trim for each bank of cylinders. Being a lean condition suspected, your fuel trims should be in the double digit positive numbers for both banks at idle and also ~2000 rpm. While monitoring those fuel trims (specifically the short term fuel trims), slowly spray carb cleaner around the gasket area... one little section at a time and see if the fuel trim goes to zero or even negative. If it does, that is your leak.

---------- Post added at 08:43 PM ---------- Previous post was at 08:39 PM ----------

Ya'll must wear some tight skirts with this ***** session going on. Waste of space, horrible forum if people want to close a thread out with posts criticizing the OP. God forbid I forgot to list a symptom that had only happened once.

Hardly a "***** session". Suck it up Francis.

 

[H0E2]

Thank you for the information.

I will try this in the morning i never did end up changing the gaskets the other day been swamped with other stuff around the house....I will post back my findings...

 

[OR VietVet]

Just another thought even if you do end up doing the gaskets, see my parts recommendations earlier in the thread, it would not be a bad idea to clean the throttle bore with carb cleaner and get some MAF sensor cleaner at the parts store and follow directions and clean the MAF. When you restart you will likely have a higher than normal idle while the MAF relearns.

Thank you for your concise, detailed and chronological list of the problems about your rig.

 

[Toyfare]

I had the same codes (P0171 and P0174), I cleared them 3 times and they kept coming back. I cleaned the MAF really well with MAF cleaner and started the vehicle. Ran rough for a few minutes and the CEL disappeared. I will see if they come back.

 

[H0E2]

I have cleaned the throttle Body and MAF and my problem has yet to return only been a day but it is about 18 degrees here. Had to pull the trigger on a new alternator as well.....also picked up a brush guard that supposedly fits my truck came off a 06 z71 the mounts don't look right think I got stiffed haha it's the dealer option guard I'll post in right forum if anyone wants it.

Thank you for the help guys I really appreciate it!!!!!

 

[Toyfare]

Codes came back. I cleaned the throttle body this time and the codes went off immediately (again!). We'll see if the codes come back AGAIN.

 

[Toyfare]

Codes came back again. It was relatively cold when they did, temps in the 20s in the morning. This weekend it was 70 and the lights went off. Maybe it's temperature related? Bad gas? Gremlins?