Tune-up idle speed
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2000 GMC Jimmy
Question: What should the RPM's be when my 4.3 liter engine is at idle?
Answer #1PARTS GUY June 23, 2012, 06:20Master
Idle speed is controlled by PCM. What problem are you having?
Replybacadebi, June 23, 2012, 06:25Rookie
Knocking at 600 rpm
ReplyPARTS GUY, June 23, 2012, 09:26Master
When you say knocking, do you mean an actual bootom end knock. If so that has nothing to do with idle speed.
Replybacadebi, June 24, 2012, 22:59Rookie
My 2000 GMC Jimmy makes a knocking noise after it warms up. There doesn't seem to be anything else wrong with it, it runs fine otherwise. I have asked several mechanics and they are stumped. I was told it could be a wrist pin? It idles at 700 rpm, is that too low? What else could cause a bottom knock?
ReplyPARTS GUY, June 25, 2012, 09:50Master
It is 12 years old. Not knowing how many miles are on the engine it could be an oiling problem.
Replyziptie12, July 31, 2012, 22:21Master
The idle speed is usually onthe underhood sticker with the engine/emissions info.Most are between 650-750 at idle in drive.If it's just one or two wrist pins as suggested while it's running kill one cyl at a time and see which cyl. the noise goes away at.