Cruise Control Anomaly - Just Started Today

[Joe Mc]

Driving around 45 with cruise set. Maintains speed on level and slight incline in roadway. When on a decline the speed drops a little but then continues to drop and the cruise doesn't pick up on it. If I hit resume it goes back to setting? Don't drive the truck but once a week nowadays but last week it was fine.
History:
●10 maybe 15 years back the cruise light on dash would come on but not hold speed when set button pressed. Ended up needing new control module that's under left battery.
●around 5 or so years back was like module went bad. Turned out being a deteriorated vacuum hose. Replaced and all has been well until today.

When I got home I gave a cursory look at the vacuum lines at the cowel area and as far as I could easily see from cowel to under battery. The seem good.

Any help appreciated. Obviously not urgent but I use cruise all the time and want to resolve.

 

[Matt42]

First thing I would do is cut off about 1/4 inch at each end of the ~1/8 inch or 5/16 inch vacuum hoses and plug them back on. You might have a microleak due to deterioration.

 

[Joe Mc]

First thing I would do is cut off about 1/4 inch at each end of the ~1/8 inch or 5/16 inch vacuum hoses and plug them back on. You might have a microleak due to deterioration.

Thanks Matt. If/when I get a day above freezing I hope to take a look at the vacuum lines.