So I’ve had a high idle for sometime and have changed the idle settings in the Xcal, set the TPS, and manually adjusted the Accufab single blade a few times over the years and have only achieved a drop from 1,250 to right around 1,000 (970 to 1130ish on the data log).

It’s spring time which means it’s that time of the year I don’t mind messing around with it a bit before I get burned out even thinking about working on the car. So I spent the last hour or so starting fresh with adjustments. First I warmed her up with a drive, then set idle in park and neutral settings to 690 & 694, then I removed the IAC but left it plugged in and duct taped the inlet/outlet shut and manually adjusted the single blade easily down to around 700 or so. Then I reset the TPS to as close to .98 as possible (ended up at .95), re installed the IAC and let her run for 10 minutes to relearn.

Zero change. I tried two other known to be good IACs with same results, even swapped in a new gasket. So I started data logging RPMs and never noticed before RPMs demanded and I see the demanded is locked in at 992 even though I set it to 690?? That makes sense as my idle bounces between 970 and 1030 give or take. She’s always had a small bit of a choppy idle, nothing new there.

So am I fighting a lost cause? If I can’t reduce the demanded idle down (even though I have in settings) then the IAC will always be bouncing to achieve that 992 RPM. I never caught this PID in data logging before and I wanted to make sure I’ve done everything on my end and I’m not missing something here before I bother Marty and Jeff.

I’m ultimately trying to cure a bad part throttle bucking trying to maintain speed in and out of pedal at anything under 35/40 in any gear then every gremlin has been fixed. It takes a seriously steady right foot to acquire any form of smooth and a left foot on standby to quickly clutch it to smooth it out. Seriously annoying in traffic or even in my subdivision.

But hey, I did get my constant running fan fixed this year! That’s 1 of my only 3 complaints. That fix was 33% of my struggles!


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