P0157

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Sep 23, 2013 | 07:08 AM

millsy23

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P0157

Can someone help trouble shoot this code? My check engile light and check fuel cap come on and stay on until reset by the garage.

I've had 2 smoke tests performed; plug wires changed twice, and an O2 sensor replaced. The MIL lights just come back on and the truck hesitates usually betwee 30-40 mph but will happen occasionally at 65-70 and other times.

Help! This is costing me a fortune!

Sep 23, 2013 | 12:12 PM

sub-moa

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From: Kentucky

What are ALL of the codes present in the memory? You should not have needed a smoke test for this concern. That would have been used for aiding with EVAP leaks and should have located the reason for your fuel cap light being on. But in my opinion this would not be a reason for the rear catalyst monitor to be lazy. The rear o2 sensors ONLY monitor the oxygen level in downflow exhaust stream flow as compaired to the front (upstream) sensors. This is how the PCM verifies catalyst performance and therefor overall emmissions. Most likely something else is causing the resr sensors not to switch correctly such as a rich/lean condition also check the connectors for corrosion from A/C condensation. and insulation dammage from heat or rubbing.