When I bought my 2004 Disco a few months ago it had blown head gaskets so I did not drive it except on the trailer and off to my shop. I used paint to mark the adjustment screws before I loosened them to do the head job and when I put it all back together and reset the cruise control and throttle the cruise control surges. Meaning it will activate and than slowely lose speed and than speed up until it hits the desired speed and than start losing speed again. It will do this about every 3-4 seconds and makes it pretty much unbareable to use the CC. I do not know if it was set right when I bought it so I imagine my paint marks do not matter. What is the correct way to set my cc so it will work properly?

 

You have one of two things going on, the most common is a vacuum leak on one of the cruise control hoses, the other could be the cruise control ECU.

 

There was a TSB on this for early model DII's.
Take the truck to your dealer and see if the TSB has been taken care of on your truck.
Otherwise it is like Mike said.

 

I doubt that TSB will pertain to his 04.

 

Good Luck,

My '03 has the dealer stamp showing that the ECU has been reprogrammed. My cable are perfectly adjusted and I have no vacuum leaks - my CC lightly surges the entire time that it is engaged. Nauseating. If you find a fix, please let me know.

-aaron
2003 SE7 100,000 miles
over $10,500 in repairs in 3 years of ownership. :-(
I LOVE this vehicle.

 

I read a post a while back about someone having slow speed loss with his cruise control, not sure if it was surging though. I believe he took out the cruise control ECU and resoldered a bunch of broke connections which seemed to fix the problem. It's always worth it to check the freebies.

 

Thanks for the tip Brian I will try whatever is free first. Mike how would i know or even check to see if I have a vaccume leak. It is a pretty new disco and when I did the HG I look over all the lines that I could visually check and they looked good. What should I do or look for?

 

Pull the hose from the vac pump and with the engine running give it a little suck and hold the pressure with the tip of your tongue - if the revs hold it's okay, if the revs drop you have a leak or a really small tongue!
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