1997 1500 5.9L 4x4 (over 200,000 miles) I miss driving my 1500 especially last week when Colorado received alot of snow. The 1500 failed emissions 3 times this year due to high NOx at idle and the cause is a suspected sunken valve in the #5 cylinder. No vaccuum leak; replaced cap/rotor, plugs and wires, and upflow O2 sensor. last emission test: HC - 1.1268 (limit 1.200) -->Pass CO - 14.3994 (limit 15.000) -->Pass NOx - 5.0481 (limit 3.000) -->Fail With alot of miles on the motor, valve job is out of the question so a reman motor. Saving the money for the new motor taking longer then aspected. Would a new cat. lower the NOx number so my truck can pass emissions? Current cat. (Magnaflow) is over 2 years old. Still plan on getting a reman. motor. Thank you for your opinion in advance.