Black Smoke (Rich Mixture)

Check the following items:

• Check for restricted air cleaner or air intake duct.
• Check fuel delivery system. On Natural Gas models, go to TEST HB, step 1)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - CNG & GASOLINE article. On all other models, go to TEST HC, step 1)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - CNG & GASOLINE article.
• Check secondary ignition system. Go to TEST JB, step 1)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - CNG & GASOLINE article.