91 Buick PA cruise control problem

[ZiggyPA]

The cruise control works intermittently on my 91 Park Avenue.
Sometimes it works, and sometimes it doesn't. The "cruise" light always comes on so I take it the selector handle is not the problem.
When it doesn't work the selected speed doesn't hold also if I try to raise it with the button, the revs get higher but the engine gives no power - as if there isn't any fuel.
When it works I can raise the speed with the button, just not by 1 mile at a time when tapping briefly.
I got the Haynes manual for the Buick fwd full size models but there isn't anything in it about this

What could be the problem, and where do I start?

[LeSabre97mint]

Ziggy

I would post this in the Buick section. There are a lot of good guys that know about the PA.

Dan

[curtis73]

At the base of the stalk there should be a couple wires visible. While you have it working and the cruise set, wiggle those wires. If you can't see the wires, flick the stalk with your thumb.

Usually most cruise problems are with the wiring in the stalk. The cruise can be on, but the wires in the stalk don't quite connect all the time.

But... with the other things you describe, I'm not sure what's going on... if the RPMs are rising, you might have a transmission problem. And if its not getting fuel, the RPMs wouldn't rise, they'd fall.

Can you maybe describe a little more what is happening?

[ZiggyPA]

Thanks for your reply. I tried fiddling with the stalk, but that doesn't seem to have any influence.
I did notice that the cruise control usually works when I hit the pedal deeper and then press cruise. After a couple of minutes (this varies) the speed begins to slip down again. When I am just pressing the pedal slightly the cruise control mostly fails.
Could this be a vacuum problem?

[ZiggyPA]

I also noticed when the cruise control doesn't work the speed seems to be slipping, it either goes down very slowly or decrease a bit and then increase a bit again and it keeps doing this.

[shorod]

Originally Posted by ZiggyPA

I also noticed when the cruise control doesn't work the speed seems to be slipping, it either goes down very slowly or decrease a bit and then increase a bit again and it keeps doing this.

Are you referring to actual vehicle speed, or just the displayed speed on the speedometer? If just the speedometer, it sounds like a vehicle speed sensor issue.

-Rod

[ZiggyPA]

No the actual vehicle speed, the speedometer is stable when it keeps increasing and decreasing speed.

[ZiggyPA]

A little correction, when the cruise control actually does engage, raising the speed by a mile by tapping the button also works.

[rodthe1st]

Not for sure about your particular vehicle, But I Know VW had a vac problem lines deteriorated, accumulator leaking.