Cruise control, '89 G20 gradually slips
 

The cruise control does work ... mostly. Especially after I've been driving and using it for an hour. I think. I know early in a trip, and most of my freeway trips are for less than an hour, it will appear to work and then slowly lose speed. If you tap the brake the speed will decrease much more quickly so it's still working when it does the gradual slip in speed.

Sometime it will hold the proper speed for 10 minutes or so then gradually slip. I'm guessing the servo is old. A search brought up a price for a reman Cardone for $73. O'Reilly's wants $90. Not that I want to rush out and buy it straight away. I could try a boneyard unit first, if I can figure out what part it is.

Pretty sure I've seen this part on my engine:

https://cimg9.ibsrv.net/gimg/chevrol...dfb0d4e40c.gif

As I look at this, could be a vacuum leak explains it.

*Edited to add*

Could be I need to clean up my throttle body moorings and install new gaskets. My research is telling me that vacuum is obtained from the throttle body somewhere.

O'Reilly's offers this throttle body repair kit. Maybe more than I planned on but who knows, may look into renewing this situation.

http://www.oreillyauto.com/site/c/de...ody+repair+kit

I have the same problem did you get it fixed ?

Not yet though I think I made some progress. I put a new gasket at the bottom of the, I guess it's the throttle body housing, it's about 5 inches in diameter, mounts between the carburetor, or rather injector body and the air filter. I was thinking maybe some air leakage at that point reduced vacuum.

I haven't messed with it for a while, I had rotator cuff surgery in August and have been gimped up pretty bad. Oh man, take care of your shoulder. I always thought I was pulling a muscle up there, turns out I was beating up the tendons.

But I'm going to be up and running pretty soon, I'll see if I can track it down.

wont be driving it until spring, but will let you know what I find

The cruise in my 88 G 20 doesn't work at all. I haven't looked into it yet. Tranny is out so my cruise isn't needed.