Idles rough after idle speed drops, seems to work better under slight load but still oscillates below 1000 rpm. Off idle and running now apparent problem. Check engine light on, changed spark plugs, changed the left and right bank O2 sensors, cleaned air filter. Coolant recently changed at dealer before problem started. Not really sure if coolant temp. sensor at fault as no change once warmed up.
Symptoms do not change with difference in ambient temp or cold start up. Whenever a load is put on engine (in gear with AC on) it seems to run better but not much. At stop I put in neutral and keep rpm up above normal idle (factory) speed of 1000 rpm. Performed wiggle test on most sensors and reseated all associated hoses and fittings with air intake system. Thinking of changing spark plugs again. As there are a lot of miles on the truck I am heading in the direction of MAF/Map or idle speed control sensor. I don't think it is related to throttle position sensor. I do not have a diagnosis tool.
Symptoms do not change with difference in ambient temp or cold start up. Whenever a load is put on engine (in gear with AC on) it seems to run better but not much. At stop I put in neutral and keep rpm up above normal idle (factory) speed of 1000 rpm. Performed wiggle test on most sensors and reseated all associated hoses and fittings with air intake system. Thinking of changing spark plugs again. As there are a lot of miles on the truck I am heading in the direction of MAF/Map or idle speed control sensor. I don't think it is related to throttle position sensor. I do not have a diagnosis tool.
Sep 11, 2011 at 3:39 PM
