Idle issue, not so smooth Options

[rjames]

My car doesn't always idle evenly. Usually when I start the car it stays right at 1000. However, sometimes after driving for a while it will go up and down in a regular pattern, fluctuating from 500-1000rpm. Doesn't seem to matter if the engine is just slightly warmed up or very warmed up. This doesn't happen ALL of the time though- I'd say a bit more then 50% of the time. The rest of the time it just stays at 1000 and doesn't move.

The only thing that comes to mind (mostly because I'm still learning about engines) is that maybe it's an injector(s), but if that was the case I'm not sure what would cause it to be so inconsistent.

I have had some problems with lower then optimum voltages at the battery, would this cause it to drop like that? I haven't taken voltage measurements at the different idle states- maybe that's the next thing to try to see if they're related?


If it was a vacuum leak I'd have a higher then normal idle, right?

[mihai914]

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