1996 deville obd codes p038 p0151 p0154 p0174 p0325.which should i fix first

Question edited for clarity. It is P-Zero 0, not P-oh O.
Please always include 'year make model' first 3 words, or it it is difficult to answer and some vehicles are slightly different or more precise and will show known issues.

P0174 - OBD-II Trouble Code Fuel System Too Lean (Bank 2)

https://repairpal.com > obd-ii-code-p0174
When a vehicle has the fault code P0174, it means that computer can no longer automatically adjust the mixture between air and fuel. Code P0174 applies to V ...

P0174 OBD-II Trouble Code: System Too Lean (Bank 2)

https://www.yourmechanic.com > Articles
Code P0174 indicates that there is a lean condition detected by the Engine Control Module (ECM). A lean condition will be created if there is too much air, and ...

P0151 Code - What Does It Mean & How To Fix It - OBD2PROS

https://obd2pros.com > dtc-codes > p0151
A P0151 code is caused by an ECM (Engine Control Module) receiving a signal indicating the O2 sensor for bank 2 sensor 1 has failed to increase the voltage ...

Code P0171 - System Too Lean: Symptoms, causes, common ...

https://www.samarins.com > diagnose > p0171
Jul 10, 2021 - The OBDII trouble code P0171 - System Too Lean (Bank 1) means that the engine air-fuel mixture is too lean, or there is too much air and too ...

It is sensor.
Censor means an official who examines material that is about to be released, such as books, movies, news, and art, and suppresses any parts that are considered obscene, politically unacceptable, or a threat to security
https://www.yourmechanic.com/article/p0154-obd-ii-trouble-code-o2-sensor-circuit-no-activity-detected-bank-2-sensor-1-by-jamahl-walker
https://repairpal.com/obd-ii-code-p0154

http://www.obd-codes.com/p0171

http://www.obd-codes.com/p0174

Check the above articles for help with these OBDII codes.

P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)
P0154 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)
P0134 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)

http://www.obd-codes.com/p0134

P0154 02 Sensor No Activity Circuit

http://dodgeforum.com/forum/dodge-intrepid/35839-service-engine-codes-for-obd-ii-engines.html

For OBD code problems check the list of help links below. Click the link below to go through its procedure.

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Diagnostic Code P2195? http://schematicsdiagram.blogspot.in/2012/02/diagnostic-code-p2195-on-toyota-avalon.html

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Diagnostic code P1330? http://technoanswers.blogspot.in/2012/02/diagnostic-code-p1330-on-kia-2wd.html

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Diagnostic code P0700, P1330, P1121? http://technoanswers.blogspot.in/2012/02/diagnostic-code-p0700-p1330-p1121-on.html

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shows error code P1330? http://technoanswers.blogspot.in/2012/02/2003-kia-sorento-shows-error-code-p1330.html

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OBD code P1330? http://technoanswers.blogspot.in/2012/02/obd-code-p1330-on-2003-kia-sorento.html

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OBD code P01300? http://technoanswers.blogspot.in/2012/02/obd-code-p01300-on-toyota-rav4.html

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OBD code P0768? http://repairhelpcenter.blogspot.com/2012/01/obd-code-p0768.html

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Evaporative Emissions System codes details? http://schematicsdiagram.blogspot.com/2011/11/evaporative-emissions-system-codes.html --------------- Engine Misfire codes?

http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html

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Misfire on cylinder 4?

http://schematicsdiagram.blogspot.com/2011/12/misfire-on-cylinder-4.html

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ABS trouble codes for all models?

http://repairhelpcenter.blogspot.com/2011/11/abs-trouble-codes-for-all-1994-00-acura.html

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Diagnostic code P0010? http://schematicsdiagram.blogspot.com/2011/12/diagnostic-code-p0010.html

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Diagnostic Code P1396?

http://howtobyme.blogspot.com/2011/11/diagnostic-code-p1396.html

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Code P0452?

http://howtobyme.blogspot.com/2011/11/code-p0452.html

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OBD code P0172 on Buick?

http://howtobyme.blogspot.com/2011/11/obd-code-p0172-on-buick-park-avenue.html

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DTC Code P0321?

http://howtobyme.blogspot.com/2011/11/dtc-code-p0321-on-buick-park-avenue.html

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Error Code P0471?

http://howtobyme.blogspot.com/2011/11/error-code-p0471-on-2007-dodge-ram-3500.html

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P0304 Error code?

http://howtobyme.blogspot.com/2011/11/p0304-error-code-on-dodge-neon.html

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OBDII scan is receiving NO BUS CODE?

http://howtobyme.blogspot.com/2011/11/obdii-scan-is-receiving-no-bus-code.html

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How to Clear OBD error Codes?

http://repairhelpcenter.blogspot.com/2011/11/how-to-clear-obd-error-codes-on-acura.html

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Diagnosis and Testing Car Components?

http://vwrepairhelp.blogspot.com/2011/11/diagnosis-and-testing-car-components.html

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Diagnostic Trouble Codes list?

Part 1.

http://repairhelpcenter.blogspot.com/2011/11/diagnostic-trouble-codes-list-for-acura_18.html

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Diagnostic Trouble Codes list?

Part 2.------

http://repairhelpcenter.blogspot.com/2011/11/diagnostic-trouble-codes-list-for-acura.html

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OBD Code is cleared but check engine light will not RESET?

http://schematicsdiagram.blogspot.in/2012/02/obd-code-is-cleared-but-check-engine.html

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Diagnostic Code 43 and 71?

http://schematicsdiagram.blogspot.com/2011/12/diagnostic-code-43-and-71-on-1991.html

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Code P0132?

http://schematicsdiagram.blogspot.com/2011/12/code-p0132-on-acura-tl.html

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P0031 code?

http://schematicsdiagram.blogspot.com/2011/12/p0031-code-on-dodge-dakota.html

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How to get diagnostic Code without OBD Scanner on Pre 1995 cars?

http://schematicsdiagram.blogspot.com/2011/12/how-to-get-diagnostic-code-without-obd.html

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OBD-II Trouble Code P0300?

http://schematicsdiagram.blogspot.com/2011/12/obd-ii-trouble-code-p0300.html

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Getting diagnostic code P0016?

http://schematicsdiagram.blogspot.com/2011/12/getting-diagnostic-code-p0016.html

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How to Read Codes from Check Engine Light?

http://schematicsdiagram.blogspot.com/2011/12/how-to-read-codes-from-check-engine.html

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Diagnostic Code P0540 continues to return and the MIL light is on?

http://schematicsdiagram.blogspot.com/2011/12/diagnostic-code-p0540-continue-to.html

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DTC Trouble Code P0401?

http://schematicsdiagram.blogspot.com/2012/01/dtc-trouble-code-p0401.html

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Car misfires and error code P0306 and P0303 is shown?

http://technoanswers.blogspot.com/2012/01/car-misfires-and-error-code-p0306-and.html

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Diagnostic code P0463?

http://technoanswers.blogspot.com/2012/01/diagnostic-code-p0463-on-ford-f250.html

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Check engine light with codes P2195 and P2197?

http://howtobyme.blogspot.in/2012/01/check-engine-light-with-codes-p2195-and.html

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Diagnostic error code P0121,P0505,P1000,P2101,P2104, P2110,P2135,P2106?

http://technoanswers.blogspot.in/2012/01/diagnostic-error-code.html

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P0174, P0037 and P2197?

http://technoanswers.blogspot.in/2012/02/p0174-p0037-and-p2197-on-toyota-rav4.html

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P0352 Obd code?

http://technoanswers.blogspot.in/2012/02/p0352-obd-code-on-toyota-rav4.html

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Error code p0402?

http://technoanswers.blogspot.in/2012/02/error-code-p0402-on-ford-escape.html

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Obd Code P0763?

http://technoanswers.blogspot.in/2012/02/obd-code-p0763-on-lexus.html

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OBD code P0301, P0430 and P0174?

http://schematicsdiagram.blogspot.in/2012/02/obd-code-p0301p0430-and-p0174.html

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OBD code P0500?

http://schematicsdiagram.blogspot.in/2012/02/obd-code-p0500-on-lexus-rx-300.html

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This will help.

Thanks.

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You have big problems here, I suggest you go to the provided links and read about these fault codes and then hire a good technician.
Ford P0171 P0174 Lean Codes

P0172 OBD II Trouble Code System Too Rich Bank 1 YourMechanic Advice

https://www.obd-codes.com/p0175


P0304 OBD II Trouble Code Cylinder 4 Misfire Detected YourMechanic Advice

probably changed the wrong sensors
The units you should have replaced are the heated oxygen sensors in the exhaust manifold before the cat converters (HO2S)
oxygen sensors(O2S ) are after the cat converters codes p 0171,0174 are lean mixture codes and p 150,p0154 are HO2S sensor faults
as the Ho2s sensors read the composition of the exhaust gas and report to the ECM to adjust the fuel settings then t faulty HO2S sensors will result in a lean or rich reading resulting in the other codes

Tim,

Yes these codes are associated with the MAF Sensor. One can trip the others as well. I would try removing the MAF Sensor and cleaning it first (brake cleaner or contact cleaner), then if that doesnt work I'd chalk up the bucks for a new sensor. Check this link for additional info on this http://www.obd-codes.com/p0174

Sincerely,

JC