Thread: Restoring Rusty
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Old 01-26-2020, 01:02 PM   #6181
Gregski
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Join Date: Aug 2014
Location: Sacramento, CA
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Re: Restoring Rusty

so I've been driving myself crazy over the past few months trying to tune out a small Idle Issue I have, not sure it's quite a hunting idle, but here's what the problem is:

Either in park or in drive my RPMs go up 50 or down 50. So I should idle at 550 RPM in Park, well I can see it drop to like 490 or go up to like 590 I also see timing go from 19* where it should be down to 16* or as high as 25*

I understand that the PCM adjusts the timing via the Idle Adaptive Spark Control aka Overspeed and Underspeed to pull the RPMs back to the desired Idle RPM, but I don't know what is causing the RPMs to be off in the first place.

My MAF grams per second may very 5.1 to 5.2 (and the frequency goes from 2527 to 2510 for example) and timing goes 21* to 20* so is that it? is that enough of a change and what can be done to make the MAF less sporatic, is it time for a new MAF?

My MAF is attached to the OEM air intake so it is the stock distance from the throttle body. I am using a cone air filter though i tried the OEM air box and stock air filter as well. Also I tried cleaning my MAF, I also tried a second MAF (same part number) I happen to have a spare and of course I re calibrated it, as it was reading up to 12% lean.

I will probably post this in the LS Swap section as well for better chance of someone seeing it
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Last edited by Gregski; 01-26-2020 at 01:10 PM.
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