Suburban - P0300, P0420, P0430 on 2000 Chevrolet Suburban 1500

K1500 Suburban with 220K miles. Starting to have some issues but has been a problem free engine for 10 years. Local mech. ran quick diagnostic - P0300 (random misfire), P0420 & 430 (Cat. Converter below threshold) All good and well but his recommendation was to replace ALL of the coil-packs and plugs. - Seriously?? Prior to having test run, rough idle was occasional, check engine light was on, so I took it in. Since test, rough idle is constant and worse than ever. I can feel the misfire, sometimes bad, others hardly noticeable. Has not progressed to the point of stalling, but it won't be a surprise when it does. At 220K miles, I am not prepared to spend a fortune with a dealer/mech., but love this truck and want to keep it on the road. Can someone help me the "try this first" list of things to consider?

by in Lakeland, FL on November 18, 2010
1 answer
ANSWER by on November 18, 2010
change plug wires and sparkplugs change converter put hi quilty converter on or you will have more problem with converter