Anyone have any input or ideas on why the cruise control on my 245 "hunts" or has problems holding the speed steady? It's not major, maybe 2-3 mph but it is very annoying as the rpms constantly rise and fall about 150-200 rpms each cycle. If it's set to 65, the speed will slowly drop to about 63, then recover and repeat over again. Vaccuum connections are good, the servo under the dash for the pedal doesn't have any holes and the vaccuum pump under the hood is working.

I installed a few of these systems years ago on others cars I had, and back then they had adjustments for sensitivity to "adjust out" this type of issue. They also had an adjustment to "center" the setting, both accessible from outside the case. The Volvo box doesn't have either. I can't believe it's the ECU that has gone bad. To me it should either work or not work.

Thanks!!

I improved the operation of my cruise by re-flowing the solder on all of the connections on the cruise ecu pcb.
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1986 240, 234K, Original owner, Boulder, CO.

If you had a "cruise ecu" your car is an earlier 200. Cruise control was done in several different designs through the 200's evolution. By '90 it was built into the LH2.4 ECU. My 84 has a Dana cruise, that appears to me to be identical to the old Dana aftermarket cruise controls we used to install in the 70's - with adjustments for centering and sensitivity. One of my Haynes manuals, I think, misidentifies the fuel ECU by showing a picture of the Dana unit. Bentley says things changed in 86, as to the location of the vacuum servo, but claims it is similar to 83-85. Was your box by the passenger's feet on the firewall?
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Art Benstein near Baltimore

I have all three versions of 240 cruise, and they all have their own separate control boxes and are independant of the LH unit. Both new types are spliced into the signal wire that goes from the spedometer to the the LH unit. That is their only connection with the LH unit. Although the latest version is "integrated" into the cars main wiring harness, the wiring is almost identical to older version, and can be used on any 240 with an electronic spedo. I am putting the latest version in my 89 because it has its own vacuum pump, and will hopefully maintain speed better.

I wonder where I got the crazy idea it was built into the LH2.4. The brain must have been taking a vacation, as I've made a lot of notes on what goes into and out of LH ecus, and never once do I recall seeing outputs for driving vacuum motors.

THe cruuise 'ecu' that I am referring to is indeed a black box, but it is on the driver's side above the clutch pedal, just dangling there.
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1986 240, 234K, Original owner, Boulder, CO.

Jessie woke me up with his post above. I apologize for sounding like I knew what I was talking about when indeed I was just full of it.

The cruise on my '90 245 has a separate control unit. It's located above the brake pedal.