Mechanics

ANY IDEAS WHAT IT COULD BE?

2003 Isuzu Axiom • 72,000 miles

Runs very rough even back fires when givin alot of gas flooring it it will take off and run ok and it idels ok but when given just a little gas or normal driving it dont want to go has codes for random misfire and both pre cad. O2 sensors but if codes are reset it will run a lot better for some time then goes back to running the same way
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Shanegorum
October 14, 2012.




What codes are you getting?
Have you checked the spark plugs and related components?
Check fuel pressure as well.


KHLow2008
Oct 14, 2012.
New plugs and it has coil packs the codes are both pre Cadillac converter o2 sensors and a random misfire 1 of the o2 sensors are new and when we reset the codes it runs ok for a few hours


Tiny
Shanegorum
Oct 14, 2012.
I need the codes, not the decription.


KHLow2008
Oct 14, 2012.
I don't have the codes did them at auto zone ill try to get them if I can


Tiny
Shanegorum
Oct 14, 2012.
Will wait for them.


KHLow2008
Oct 14, 2012.
Ok 1 code is p0151 then it just says random misfire


Tiny
Shanegorum
Oct 14, 2012.
And po131 pd


Tiny
Shanegorum
Oct 14, 2012.
Here are the diagnostic aids.

Diagnostic Aids

Check for the following conditions: Check HO2S pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent ground in signal wire between sensor connector and sensor.

Check PCM grounds.

Check fuel pressure.

Perform injector balance test.

Vacuum leaks: check for disconnected or damaged vacuum hoses and for
vacuum leaks at the intake manifold, throttle body, EGR system, and PCV system.

Exhaust leaks: an exhaust leak may cause outside air to be pulled into the exhaust gas stream past the HO2S, causing the system to appear lean. Check for exhaust leaks that may cause a false lean condition to be indicated.

MAF sensor: the system can go rich if MAF sensor signal indicates an incorrect engine airflow measurement that is not correct. Disconnect the MAF sensor to see if the lean condition is corrected. If so, replace the MAF sensor.

Fuel contamination: water, even in small amounts, can be delivered to the fuel injectors. The water can cause a lean exhaust to be indicated. Excessive alcohol in the fuel can also cause this condition. Check for fuel contamination.

If none of the above conditions are present, replace the suspect H02S.
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KHLow2008
Oct 15, 2012.

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