Engine: 4.4 v8 (267) Can
Carburetor: Rochester 2bbl DualJet E2MC
Trying to figure out why my HC and CO flips fail on idle and high idle
Idle - Fail
HC ppm: 685 (220 passing) Fail
CO%: 0.18 (1.20 is passing) PASS
High idle - Fail
HC ppm: 65 (220 passing) PASS
CO%: 1.38 (1.20 is passing) FAIL
1. CAT was installed about 3 year ago.
2. New MAP sensor about 2 years ago.
3. New O2 sensor installed about 2 year ago
4. New ECM & PROM installed about 2 years ago
5. New EGR valve installed about 2 years ago.
6. Several vacuum leaks fixed.
7. New air cleaner
8. New PCV value installed
8. Distributor, rotor, Plugs, Wires installed less than 3 weeks ago. (one wire was found burned through from touching the manifold).
9. check engine light is not on.