I've noticed for the last probably 3-4 days, my cruise is just unusable. I'll set it for a speed, and it'll progressively hold speed worse and worse, vary speed farther and farther from set, and generally throw me around as it romps the gas instead of easing in and out of it like it used to.

It feels a lot like what happens when I cheat on low speed limit roads with the cruise in a lower gear, just the car making very abrupt transitions, except now it's happening in sixth, and it's very uncomfortable to have my head keep getting slammed into the headrest.

I had the cruise set at 67 at one point on my way home, and it was going as low as 63 and as high as 71. At another point, set at 75, it was going on a 74-82mph swing.

This was on flat ground, at least initially. Hills would make the variance worse, and whatever speed the car was at at the top of the hill wouldn't neccesarily be adjusted down once the car was on level ground again.

Search is busted, but i did try googling it, restricted to this domain and didn't see anything. Anyone have any experience with this? Any info they can share with me?

 

So interestingly, I'm still seeing this problem intermittently, but it's not the cruise doing it!

Watching my speedo while holding a constant RPM, occasionally the MPH changes will come very quickly, and other times it'll say i'm doing a speed while cruising at an RPM that doesn't correspond to it.

At a guess i'm thinking the VSS is dead but i'd love to know if there's a common failure that corresponds to this behavior... anyone seen anything?

 

Got the same problem.

I have a yellow jacket speedo calibrator and an AEM EMS. The EMS doesn't have a bracket and will slip down and pinch one of the wires for the speedo signal when I go over bumps every now and again. Gives the same result...the speedo goes wild and cruise surges.

 

I have neither YJ or AEM.

Where's that wire gettin' pinched though?

 

is the speed read off of the tranny or off of the hubs? if it takes the readings off of the teeth on the hubs clean those off.

 

The vehicle speed reading is taken from the VSS on the trans, not the ABS sensors on the hubs.

 

You might do well to borrow a scan tool with R/T diagnostics and check to see what speed the ECU is getting. I am having a similar issue - and was very surprised to learn the ECU always has the correct speed. This seems to indicate an issue in the cluster itself, as all wiring checks out correctly - and obviously the VSS is OK.

I hope that you get some responses here that I can use for my own benefit as my thread has gone largely un-noticed...

Sleeper

 

[QUOTE=negcamber,May 27 2008, 06:08 AM]Got the same problem.

I have a yellow jacket speedo calibrator and an AEM EMS.

 

Iiiinteresting! I'll track down a scantool. Thanks for the headsup on that one.

Negcamber, where's this wire, man?

 

The one marked Step 5 Clamp T-tap is where I'm having trouble...but note that the blue/white (marked "Crimp female") wire is the speed signal wire and may give a similar problem.