Fast idle

I have a 96 Tahoe with the 5.7 with 175,000 miles. The accelerator pedal started sticking at idle and I would have to quickly stomp it to unstick it. It would only happen at idle. It also began idling at 1,300 - 1,500 rpm, and drop down to 700 - 800, then back to the high idle. It would idle up and down sporadically but mostly stay at the high idle.

I pulled the throttle body and it was pretty gunked up so I cleaned it and replaced the Idle Air Controller that is mounted on the side of the throttle body. I put it back together and now it idles at a steady 2,300 rpm. I pulled the throttle body back off and double checked that the manifold gasket was good. The good news is the accelerator doesn't stick anymore.

I found a very small (approx. 1/16") vacuum hose that has one end connected to a piece on the intake to the right of the throttle body and I can't find anywhere that the other end connects. It is a small vacuum leak but holding my thumb over the end doesn't change the way the engine runs. It doesn't miss or backfire. It actually runs better now but I can't get the idle down below 2,300. Help!

put up a picture of this vacuum line and where the one end is attached, some one will know I haven't messed with the obs in a long time so no idea off hand myself without a visual, as far the the idle you may just need to drive it a ways and let it relearn, try disconnecting the battery for about 10-15 minutes also so it can all reset then just drive it and let it try and do it's thing.

as much as i messed with mine it never had to relearn idle much past 30 seconds and even then it never went that high. thr only time it idled that high was when i forgot the brake booster vacuum line.

If you’re super duper sure it isn’t vacuum, could the accelerator cable be bound?

My truck only increased 100-200 RPM with a vacuum hose broken. If there's nothing wrong with the accelerator cable you might want to put the old idle air controller back in and see if you have a bad one. If you post a pic of the vacuum hose I'll see where it goes.

Thanks everyone. I'll post a pic of the vacuum hose tomorrow. I'll also try these suggestions. I'm thinking I can just disconnect the accelerator cable and see if the idle drops. That should let me know if it is bound. If that's not it I'll clean and re-install the old idle control and see if that makes a difference.

I've let it run 10 minutes a few times to see if it would reset itself but it didn't. I'll keep y'all posted.

Thanks everyone. I'll post a pic of the vacuum hose tomorrow. I'll also try these suggestions. I'm thinking I can just disconnect the accelerator cable and see if the idle drops. That should let me know if it is bound. If that's not it I'll clean and re-install the old idle control and see if that makes a difference.

I've let it run 10 minutes a few times to see if it would reset itself but it didn't. I'll keep y'all posted.

Thanks everyone. I'll post a pic of the vacuum hose tomorrow. I'll also try these suggestions. I'm thinking I can just disconnect the accelerator cable and see if the idle drops. That should let me know if it is bound. If that's not it I'll clean and re-install the old idle control and see if that makes a difference.

I've let it run 10 minutes a few times to see if it would reset itself but it didn't. I'll keep y'all posted.

Thanks everyone. I'll post a pic of the vacuum hose tomorrow. I'll also try these suggestions. I'm thinking I can just disconnect the accelerator cable and see if the idle drops. That should let me know if it is bound. If that's not it I'll clean and re-install the old idle control and see if that makes a difference.

I've let it run 10 minutes a few times to see if it would reset itself but it didn't. I'll keep y'all posted.

Thanks everyone. I'll post a pic of the vacuum hose tomorrow. I'll also try these suggestions. I'm thinking I can just disconnect the accelerator cable and see if the idle drops. That should let me know if it is bound. If that's not it I'll clean and re-install the old idle control and see if that makes a difference.

I've let it run 10 minutes a few times to see if it would reset itself but it didn't. I'll keep y'all posted.