o2 sensors/cats vs. fuel pump
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05-08-2013, 10:23 AM
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o2 sensors/cats vs. fuel pump
Newbie here with '04 Ram 1500 5.7L 4x4...I know its long, but the devil is in the details.
Oct: ODB codes show bad O2 sensors in 1/2 and 2/2. Replaced.
Nov/Dec: Go to fill up - clogging or vent problem prevents steady fill. 3 or 4 seconds, fuel drains in, 3 or 4 seconds....repeat.
Around the same time, I notice my gas mileage begin to taper off. Not severly but enough to think something may be acting up.
April - filling of gas tank spontaneously returns to normal. No signs of what may have fixed it.
April - truck has sporadic episodes of running rough, hesitation/surging, and stalled a couple of times. ODB codes P0171, P0174 (lean conditions both sides) P0420 and P0430 (cat efficiency below tolerance, both sides)
April - dealer. flashed the PCM per TSB, changed plugs and wires, cleaned throttle body, cleaned fuel injectors, and other minor stuff unrelated.
Drove it for 200 miles and the problem resurfaced. for the next 10-15 miles I had a loss of power from start, hesitation/surge, up and down RPM's at idle, misfire between 1200 and 1500 RPMs under light acceleration in overdrive, rich smell and black smoke. Then, it spontaneously fixes itself and returns to normal. When returned to the dealer, I was told both CATS are bad 3 of my O2 sensors have failed. I don't believe it.
Sitting in the driveway yesterday with the truck in park and RPMs at 2K, I hear a click under the hood and the RPMs drop and the truck begins to poorly. After a few seconds, it recovered. Another click, poor running conditions and it recovers. When driving, if I mash the gas, it appears to get past the issues but will revert back eventually.
At my wits end. O2 sensors and CATS because scan tool says so? Or could it fuel relay/fuel pump/fuel filter problem associated with a possible clog in the fill line (not sure how that would have happened) and/or a failing relay and/or pump?
My thoughts are to replace the pre-cat O2 sensors first. (least time/money). Next would be to drop the tank and inspect it for debris etc. and replace the relay and fuel pump/filter as necessary.
I would appreciate anyone's thoughts from this forum!! Thank for helping the new guy.
Cory
Oct: ODB codes show bad O2 sensors in 1/2 and 2/2. Replaced.
Nov/Dec: Go to fill up - clogging or vent problem prevents steady fill. 3 or 4 seconds, fuel drains in, 3 or 4 seconds....repeat.
Around the same time, I notice my gas mileage begin to taper off. Not severly but enough to think something may be acting up.
April - filling of gas tank spontaneously returns to normal. No signs of what may have fixed it.
April - truck has sporadic episodes of running rough, hesitation/surging, and stalled a couple of times. ODB codes P0171, P0174 (lean conditions both sides) P0420 and P0430 (cat efficiency below tolerance, both sides)
April - dealer. flashed the PCM per TSB, changed plugs and wires, cleaned throttle body, cleaned fuel injectors, and other minor stuff unrelated.
Drove it for 200 miles and the problem resurfaced. for the next 10-15 miles I had a loss of power from start, hesitation/surge, up and down RPM's at idle, misfire between 1200 and 1500 RPMs under light acceleration in overdrive, rich smell and black smoke. Then, it spontaneously fixes itself and returns to normal. When returned to the dealer, I was told both CATS are bad 3 of my O2 sensors have failed. I don't believe it.
Sitting in the driveway yesterday with the truck in park and RPMs at 2K, I hear a click under the hood and the RPMs drop and the truck begins to poorly. After a few seconds, it recovered. Another click, poor running conditions and it recovers. When driving, if I mash the gas, it appears to get past the issues but will revert back eventually.
At my wits end. O2 sensors and CATS because scan tool says so? Or could it fuel relay/fuel pump/fuel filter problem associated with a possible clog in the fill line (not sure how that would have happened) and/or a failing relay and/or pump?
My thoughts are to replace the pre-cat O2 sensors first. (least time/money). Next would be to drop the tank and inspect it for debris etc. and replace the relay and fuel pump/filter as necessary.
I would appreciate anyone's thoughts from this forum!! Thank for helping the new guy.
Cory