I have a 96' Sierra 5.7L with 150k ,a few weeks ago I notice the engine idled rough at a red light ,acceleration and performance are not affected and no check engine light or codes. I started to pay special attention to the symptom and found it started and idled great as usual but after the engine came up to temperature and the tach indicated about 500 rpm when stopped in gear there is a noticeable rough and loping idle.If anybody could narrow down the possibilities ( my Chiltons gives about 10 different possibilities ) I would appreciate any and all input.
I have a 96' Sierra 5.7L with 150k ,a few weeks ago I notice the engine idled rough at a red light ,acceleration and performance are not affected and no check engine light or codes. I started to pay special attention to the symptom and found it started and idled great as usual but after the engine came up to temperature and the tach indicated about 500 rpm when stopped in gear there is a noticeable rough and loping idle.If anybody could narrow down the possibilities ( my Chiltons gives about 10 different possibilities ) I would appreciate any and all input.