My 1999 Sonoma with the 4.3 is having power/acceleration problems. I get four fault codes that will flag my check engine light on occasion they are, P0171, P0174, P0151, and P0154. I have changed the bank 2 O2 sensor and it didnt do anything. Any suggestions on this problem would be helpful.

When engine management light is on I would run diagnostics on it, it will tell you the fault code to the problem.

Have you checked the throttle body? That requires an annual cleaning and could very well be the cause of the issues you have with your Honda.

-Alex K.

need a code scanner to erase codes.

If the check engine light is on I would have that checked first. The trouble codes in the computer will help point you in the right direction for troubleshooting.
You could have a sticking fuel injector, or an ignition problem, or both.

All fault codes can be checked out at http://www.bluejag.co.uk but here are the results for some of yours. You can ignor P1111. Looks like a faulty plug or coil pack cylinder 2

Fault Code:- P1314 Indicates a Power-train fault


The fault is generally due to a problem in the Ignition or Misfire area


Fault Description: Misfire rate catalyst damage -bank 2 NOTE: This DTC will flag only when accompanied by an individual cylinder misfire DTC: P0300 - P0306

Action of ECM:- ECM Default:- Maximum engine speed reduced


After clearing the DTC, complete the Misfire monitor drive cycle
Check for a reoccurrence of fault DTC.

Possible Fault:- Cylinder compression low Worn camshaft / broken valve spring(s) Fuel delivery pressure (low / high) Fuel injector(s) restricted / leaking Fuel injector(s) continuously open Fuel contamination Fuel injector circuit fault(s) (Injector DTCs also flagged) Spark plug failure / fouled / incorrect gap ECM to ignition coil primary circuit fault (Cylinder misfire detected DTC also flagged) Ignition coil failure
Fault Code:- P1316 Indicates a Power-train fault


The fault is generally due to a problem in the Ignition or Misfire area


Fault Description: Misfire excess emission NOTE: This DTC will flag only when accompanied by an individual cylinder misfire DTC: P0300 - P0306

Action of ECM:- none


After clearing the DTC, complete the Misfire monitor drive cycle
Check for a reoccurrence of fault DTC.

Possible Fault:- Cylinder compression low Worn camshaft / broken valve spring(s) Fuel delivery pressure (low / high) Fuel injector(s) restricted / leaking Fuel injector(s) continuously open Fuel contamination Fuel injector circuit fault(s) (Injector DTCs also flagged) Spark plug failure / fouled / incorrect gap ECM to ignition coil primary circuit fault (Cylinder misfire detected DTC also flagged) Ignition coil failure

Fault Code:-
P0302 Indicates a Power-train fault


The fault is generally due to a problem in the Ignition or Misfire area


Fault Description: Misfire detected ?€" cylinder 2

Action of ECM:- none


After clearing the DTC, complete the Misfire monitor drive cycle
Check for a reoccurrence of fault DTC.

Possible Fault:- Refer to P0300 Possible Causes

ok get in contact with i garage that have a data logger to clip on to your obd test outlet. you drive fore some days and just write the time down when th car is doing poorly then the garage can take the obd logger and se all engine parameters on that time the engine was lacking power. after that the garage can fix the problem just locking at fault codes don't give you the full picture. good luck Han

Check the fault codes anyway. Did you do this fuel pressure testing while the loss of power was occurring? If no the test is invalid.

You should have your cat. checked make sure there is no restrictions in your exhaust system.

This code is not documented so the code reader is giving a false reading.
If the car runs OK and check engine light is not on, I would forget about it.

Hi

If the engine is running without any problems then The fault code which has flagged the checked engine light will either pertain to the upstream O2 sensor, a drop in catalytic efficiency, an EGR issue, or maybe even an EVAP issue.

A lot of EVAP issues can be resolved by simply ensuring that the fuel filler cap is on securely, otherwise a vacuum leak will be detected in the system and the check engine light will come on.

A drop in catalytic efficiency (P0420) is usually temporary and will stay away after a reset.

EGR issues can sometimes be rectified by removing the EGR valve and cleaning it, and the ports on the intake where it was sat, but there are occasions when it has to be renewed.

The O2 sensor issues are a wee bit different. There are a number of fault codes which relate to the O2 sensor, and which make the O2 sensor look faulty, when the O2 sensor is actually attempting to rectify a problem from elsewhere and isn't faulty at all. However, they could also be due to a fault with the O2 sensor. Basically, further checks should be made before condemning the O2 sensor should the fault code relate to the sensor.

Have a code read done and then have the codes reset and see what comes up.

Regards

Geordie