Idle RPMs

[Suburban-97]

My truck runs at about 650rpm at idle when warm. My wife's car runs at 800rpm, but hers is a 4Cyl. At 650 the engine runs absolutely smooth, I actually do not worry about anything, but I was just wondering whether 650 is the normal number I should see or not..

[MIkeman28]

I run at 850. I wouldnt compare toa 4cyl tho. If it works good, dont fix it

[Suburban-97]

MIkeman28, after doing a little browsing on the 'Automotive Repair Reference Center' website at the library, I found a document containing the gasoline engine tune-up specs for K1500 Suburbans from 1996-2000. Among spark plug gaps and fuel pump pressures, there are the idle speed rpm values.

Here they are:

(VIN W) 4.3L - 600 rpm
(VIN V) 4.8L - Idle speed is maintained by the PCM
(VIN M) 5.0L - 650 rpm
(VIN T) 5.3L - Idle speed is maintained by the PCM
(VIN R) 5.7L - 660 rpm
(VIN U) 6.0L - Idle speed is maintained by the PCM
(VIN J) 7.4L - 750 rpm

..so I guess mine runs like it should and yours is a little too high at 850

[MIkeman28]

true. But like I said, idle at 850 is not doing any harm, so no need to fix anything. Anything over that and I would probably check my intake gasket