High Idle Problems

I've had a high idle issue plaguing me for far too long. On cold start it will idle at 1250 or so and as it warms up it will go upwards of 1500-1800. I've replaced the PCV and hose. I went through all of the vacuum hoses and other components on the right side of the plenum checking for cracks or leaks. The idle set screw is all the way in (it was that way when I bought it). The volume air flow sensor looks to be fine and had correct resistances. I checked resistances on the TPS. Nothing about the performance is acting up. It has plenty of get up and go for the 3.0. I don't know where to go from here. I've looked the throttle body over several times, cleaned it out with throttle body cleaner, and nothing is holding it open. I thought it might be the idle adjust valve, but that looks fine. There's a slight, intermittent put-put sound coming out of the exhaust and it smells kind of funny. I'm not sure what would cause such an awfully high idle that would not have an impact on it while driving.

Compounding my issues, I went and checked the ignition timing for the first time and holy moly. If my light is working properly, it says my timing is over 60° off. I followed the procedure, double checked that I was on #1's wire, that I had jumped the designated pins, and that I was hooked up to the battery. I've not yet replaced the distributor/rotor, but I don't see how that would fix if it's not misfiring. I can't help but wonder if it's not possible to properly adjust ignition timing with the idle issue going on.

I guess my biggest question is which problem should I try to sort out first, the idle or the ignition timing? I can't help but think that they are contributing to one another and I can't get this solved with both going on at the same time.

On the bright side, I replaced the valve cover gaskets, adjusted the valve clearance, installed upgraded fuel injectors, and replaced all the coolant hoses. Not a drop has leaked since and it feels like it's got more power going uphill. (The idle issue predates all of this work).

 

Well after nothing else working, I got a junkyard throttle body that had an IAC that wasn't seized up like mine. After checking the TPS, I screwed the IAC retaining ring-screw-thing in further and it brought the idle waaay down. It's now idling 850-1000. A little more tuning and setting the ignition timing, it should be all set.

 

Well sounds like your pushing through and getting things done, did you do the 4 hole injectors ? And on the throttle body did you use that video the guy did recently on his dads truck for reference. Know which one I’m talking about, I think he did the same thing, I found that pretty informative and may check mine as I’m having trouble passing smog.

I reset my timing to like 14 degrees but I’m thinking now I’m going back to 10 and putting my 1 hole densos back in. I did notice though I got more power with the upgraded injectors.

 

They're the 2 hole injectors from Precision Auto Injectors. Sure feels like it gets up the hills a little easier.

Not sure which video you're referring to, but this is the only one I found related to the IAC. https://www.youtube.com/watch?v=i3ITYoNAUTY

I've still got to do my ignition timing. Curious if/how that will affect the idle and/or performance.