Question about 2002 Chevrolet Tahoe

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Misfires during a cold start, shows running lean on both banks. Tried changing the spark plugs and the 2 oxygen sensors before the cat.

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I am having the same problem. I have an 2004 Tahoe and have had the same problem for the last 2 years. The funny part is that is never happens in the summer and only happens when it is below freezing for the 1st start of the morning. I recently hooked up to a check engine light computer and I got 3 codes. One is P)171, PO174, PO300- They mean too lean in banks 1 and 2 and a misfire similar to yours. I just replaced all the plugs and wires this summer and I am still having the problem. Does anyone have the same problem or a solution to this issue. I have read that it could be a vacuum hose or O2 sensor that is bad but not sure. Any help? Thanks. Brett

Posted on Nov 18, 2010

  • pickity23 Nov 18, 2010

    I forgot to mention that when I start it up for the first time of the day it also mis idles and almost dies for the first 20 seconds when it is cold and then it settles back to normal idle and is fine after that.

  • Truk1 Dec 29, 2010

    This is likely a vacuum leak but even more common is a intake manifold leak. It is a very common problem on the Chevy. Lots of people throw a huge amount of money away chasing it. Try new gaskets and make sure to check the manifold for warping. If it is warped you will need a new one.

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4 Answers

Code p0153..p1153


Rowland, Code p0153 Faulty oxygen sensor.
http://www.obd-codes.com/p0153
Code p1153 Probale faulty oxygen sensor.
PCM detect less than 55 lean to rich or rich to lean switches
P1153 OBD Trouble Code

Check the attached links,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."

Mar 21, 2016 | GMC Cars & Trucks

1 Answer

What are the probable causes of DTCs P0300 and P0316?


code p 2274 refers to heated oxygen sensor(HO2S) 3 bank 1 signal stuck lean or oxygen sensor(O2S) signal stuck lean===causes for both--wiring ---HO2S--fuel pressure --injectors --intake leak
code p 0300 refers to random /multiple misfires detected ===causes --spark plugs -- HT leads injector/s--ignition coils --low compression --wiring
code p 0316 refers to misfire detected during start up---first 1000 revolutions ===causes --engine mechanical fault---wiring---ignition / fuel system---injector
in all codes the injectors show up as a problem cause and if you couple that with low fuel pressure issues you may have a pointer to the real cause
have a pressure test done on the fuel manifold top check for pump fault , filter blockage and faulty pressure regulator
check /clean injector tips as they could be suffering from contamination problems and not operating freely ( good fuel injector cleaner)

Oct 11, 2015 | Cars & Trucks

1 Answer

4.0l 6 cylinder. What are the probable causes of DTC P0171?


no. (but the isc valves loves to stick but will not cause black smoke)
the 4.0L is one of 5 million made, it's well known,
the black smoke don't lie. it's rich and the cat seems burned up too.
as with black smoke the cat will try to catalyze all that and glow red hot. is your cat missing?>
so why not believe the code 171, its real and is catastrophic failure. there are 2 engines here, FED and California.(exhaust)
(2 different exhausts and sensors there.
as they say, fix what is OBVIOUSLY bad, 171
(find why using tools or inspections)
Fuel System Lean (Bank 1)in most cases the exhaust is cracked near B1S1 0xy sensor
this causes it to stick at 0volts, (lies) and the PCM sees that obvious lie then goes rich. (limphome rich)
if the pcm cant measure oxygen, it must now guess at fuel trim.(bad that.)
it goes rich, so you dont melt pistons running lean.
(by design)

bad front oxygen sensor (aka , up stream bank 1)
in calif cars, it can have a split exhaust on the I6 and have 3 sensors. (hope not yours, do look..)
most have 2 sensor, front and the useless behind cat sensor(B1s2)
S2 is useless for running mix, the rear is for smog test the cat.

so it rich, and now misfires. and the spark tips are black.
and it misfires to bad it can even idle, sure. (Drops)
the cause, is too rich.
the 171 means the PCM sees it stuck at 0v forEVER.

there are in fact other causes.
but these 2 are top cause.

on all 3 of my 4.0L engines
the exhaust manifold cracked on the under side.
side facing block. (i use a hose to ear to hear the putt putt puts, (with FULL PPE protection from burns from a dead cold engine.) ask how.
even the SST exh. man. did that.

or the header flange gasket is TOAST. (that too putts when bad.)

Aug 03, 2015 | 1996 Jeep Grand Cherokee

1 Answer

Hey I'm mike. Here want going on my s10 blazer


to start with the in front of the cat is different to the one after the cat and will produce different signals for the ecm and that will throw up fault codes

Code p0154 refers to heated oxygen sensor(HO2S) 1 bank 2--no activity detected--===causes --Wiring--HO2S-- ECM

replace with correct sensor (heated sensor )

code p0300 refers to random/ multiple misfires detected---===causes---spark plugs--HT leads --injectors---ignition coil/s---low compression---wiring

The HT lead should be replaced as by pulling it off the plug the internal resistance has been damaged. Check the injectors are firing correctly as my guess is that the injector is faulty and that is what set you to change the HO2S sensor

Aug 31, 2014 | Cars & Trucks

1 Answer

I have a 1997 ford explorer and it reads 1 2 4 6 cylinders are misfiring and bank 1 and 2 are lean and bank 2 sensor 2 problem please help!!!!


If the front oxygen sensors have over 100,000 miles
on them change & then work on vacuum leaks in exhaust
prior to converter & then ignition misfires

Spark Plugs--every 3 years
Clean MAF Sensor

Exhaust Converter may be shot,then only last 12 to 14 years
If so-- then do the rear sensors as well

Nov 27, 2012 | 1996 Ford Explorer

2 Answers

I HAVE A P0300 OBD CODE I DID A COMPRESSION TEST TO ENGINE AND IT PASS THE TEST,I DID CHECK EGR VALVE,CHANGE SPARK PLUGS,IGNITION WIRES, CAP AND ROTOR, I DID CHECK TPS SENSOR MAF SENSOR,FUEL PRESSURE,AND...


p 0300 code is for random misfires
random misfires are more from dirty /faulty injectors or low fuel pressure than anything else
have a pressure test done to check pressure regulator , filter and pump operation
use a can of quality injector cleaner or remove and clean the injectors

Apr 06, 2017 | 1997 Nissan Pathfinder

2 Answers

Ford f150 2003 po171 always lean bank 1. replaced bank 1 o2 sensor smoked intake. replaced egr valve. still code po171 short term trim 0123 but long term trim is up bank 1 30 anb bank 2 is 27. idle is a...


Code Po171 indicates a lean condition on cylinder bank #1 of the engine. This is the drivers side of the engine. I would suggest replacing both front oxygen sensors as a pair to start. An oxygen sensor has a life span of about 5 years and yours are now 9 years old if they are original. When they get older they are slow to respond to changes in the oxygen content of the exhaust and can trigger a code Po171. If you continue to have the same code set after the replacement of both oxygen sensors then it is time to find out why your engine is running lean. Some of the most common causes are an ignition misfire and a vacuum leak. I have also seen Fords EGR flow sensor (known by Ford as Delta Pressure Feedback sensor) to cause problems like that as well. A good mechanic with a scan tool can usually spot a problem like that in a few minutes.

Mar 01, 2011 | Ford F-150 Cars & Trucks

1 Answer

2003 c 230 code p0171 replaced air flow sensor no vacume leaks still have code at long idle


fault code P0171 System Too Lean (Bank 1), this fault could be occurred because of faulty upstream or downstream oxygen sensor of bank one you must check the actual value of upstream and downstream oxygen sensors, if the oxygen sensor values are same both side bank one and two check subpressures for spark plugs (spark plugs wires ) and spark plugs and ignition coils, can do one thing to find out easily, swap spark plugs subpressures and ignition coil between both banks after that clear code and start if the code change to P0174 System Too Lean (Bank 2) you can understand that's the fault create by one spark plug or wire or coil then swap one by one and you be able to find which one is the faulty one replace it.is this information helped you?

Oct 25, 2010 | 2003 Mercedes-Benz C-Class

1 Answer

My 2001 Corolla displays P0171 after it idles for a minute or two. If I drive it hesitates (especially under hard acceleration) and starts also displaying P0300, P0301, and P0302. If I clear the codes...


po171 is lean on bank 1--===causes --MAF/VAF sensors --injectors ---HO2S (heated oxygen sensor)
po300 is random misfires and po301, 2, 3 4 5 6 etc is the cylinder that is misfiring
most likely that the fuel pressure is below the required pressure either from the pump or blocked filter or the tank not venting properly--- (EVAP) problem
check the fuel pressure ( minimum of 45-65psi) --problem pressure regulator , pump or filter
replace the heated oxygen sensor on bank 1 ( in the exhaust manifold before the cat converter) as it reports to the ECM to get the correct air/fuel mix

Jul 19, 2017 | 2001 Toyota Corolla

1 Answer

I have a 2003 Tahoe. The check engine light is on.


i would start easy and run a bottle of injector cleaner through it. Good Luck

Mar 14, 2009 | 2003 Chevrolet Tahoe

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