Well, I may be posting somethin you already know, but did you lengthen your throttle cable? As well as you TV cable to the trans? When you raise it up, it shortens these cables. I don't know if it would make it idle that high though, but it would definetly make it idle higher. Also, be careful with that TV cable. You can fry the trans if it isn't set right. I am assuming its a 700r or a 4l60e auto trans. If its a standard, ignore all that about a TV cable. TV is throttle valve cable. Also, there isn't an idle screw on those throttle bodies. Just sayin.

Those spacers are such a waste of money. You not only have a vacuum leak now, but the spacer blocks the vacuum port to the fuel pressure regulator that is built into the injector housing so your fuel pressure will be too high all the time and your gas mileage will go down the drain as you burn up the cat.

Now wasn't that fun?

You need to plug what ever vacuum leak you created.

check idle screw near throttle body .

You now have a major vacuum leak. Recheck your work. You did something wrong or it's the wrong part.

OR, the idle air control valve is stuck.

I have a 1994 gmc sierra with 103,000 miles. I put a throttle body spacer on it and ever since I crank it up and it revs to 3000 rpms and idles there. How can I fix this issue? It didn't start until the spacer was installed