Car wont idle any lower than 1100 rpm even when warm

FYI I have been having a weird varying high idle. The idle ranged from 750 to 2000 rpm cold and warm. So today I took my throttle body and IACV off my 98 legacy gt. I replaced them with a throttle body and IACV from a 98 gt parts motor I had lying around that I cleaned thoroughly with throttle body cleaner the other day. After doing this I started up the car and the idle went straight to 3000. I immediately checked to make sure all hoses and electrical plugs were connected and tight and they were all good. So I assumed the IACV I swapped in must have been bad so I cleaned the one I took off with throttle body cleaner and through it back on. Now the idle is constant 1100 rpm all the time cold and warm. It no longer will go to 1500 or 2000 like it used too, but it also used to sit nicely at 750rpm half of the time. Any help would be appreciated. Thanks

vac leak

 

spray the hoses with carb cleaner or starting fluid while it idles.

hopefully it will rev up when the ''cleaner'' is sucked in.

Or there's carbon build up inside the IAC not allowing it to close. They usually need a good cleaning around 100k.

I'll check for vac leaks and the car has 208,000 miles on it. I cleaned out most of the carbon but there still could be a good amount still in there.

You might need to adjust your TPS voltage since you installed a new TB, assuming it has new TPS. Or take your original TPS sensor install back to new TB.

I'll

Try swapping the old tps in later today.

Swapped in the old tps and adjusted its position while the car was running. Lowest rpm i could get was 1075 with it roughly in the center position, moving it in either direction cause the idle to rise.

Make sure the vacuum control unit for the cruise control is together. This vacuum leak will also raise your idle. as if it's trying to set a speed. This will occur even if you have a CEL.

 

O.