Idling at 650 to 750 RPM's

[9t8z28]

Help! My car is idling at 650 to 750 RPM's. Is this normal? The car is basically stock with only a Pypes muffler.
Before it was idling at 1,100 to 1,200 RPM's with the check engine light on. I scanned it, and replaced the EGR. Check Engine light went out. It still idled high. Then I put the muffler back system on, and still idling high. Today, I pulled into the gas station and shut the car off. When I went to start it nothing happened. I got out and tightened the battery cables, then it started but was idling way to low. NO CHECK ENGINE LIGHT!!

Sorry for the long story but whats up, is this normal?

[BlackLT1Z28]

Are you judging the idle right at start up or after it warms up? Usually, on cold start up, the engine will idle a little higher for the first 10-20 seconds to get fluids going and such. About the range of 1.5K RPM or so. Oil pressure will also be up. Then the engine will idle at about 1K or so until it warms up. But once the engine warms up and reaches operational temps, the idle should be back down to where it should be idling at.

[9t8z28]

The RPM's are very low when warmed up and oil pressure is around 40. What should the car idle at?

[Stricken1]

Mine is always around 700 to 750.

[BlackLT1Z28]

The RPM's are very low when warmed up and oil pressure is around 40. What should the car idle at?

RPM's should be relatively low when warmed up. 650-750 sounds about right. I don't know the idle of LS1's though, my LT1 idles at 600 when warm.