What rpms should my M52 idle at when cold? Moderate cold (30-40F) it bounces from 1500 to 1200 and back until it finally settles at normal idle speed. Below 30F it jumps much higher (1700+) holds there for a few seconds, then steps down in stages to normal idle. Is this SOP or do I need adjustments made?

I've got the same symptoms as you. So far I'm leaning towards the Idle Control Valve (ICV?) as the cause of them problem. Especially since it only idles this way every other cold start but it's becoming more and more frequent.

I guess while mines in the shop for a clutch, I'll have to ask my mechanic about that, he's got $800 coming already, what's a few more.

I had an intake leak recently (loose hose clamp) that caused this in the morning. The ICV would do it's best to compensate, and that was the cause of the surging from my car...

I'll have to check that too. I've often thought that mine was running lean. When you engage you cruise control does it do it smoothly or does it surge a little like when you hit accelerate? Mine does, and I'm wondering if that's all caused by the same problem.

I'll have to check that too. I've often thought that mine was running lean. When you engage you cruise control does it do it smoothly or does it surge a little like when you hit accelerate? Mine does, and I'm wondering if that's all caused by the same problem.

Yeah it could be sticking throttle cables. I haven't used my cruise on my car in ages (over 2 years or more), so I'm not 100% sure how it engages. I thought it did it smoothly?

If your cables on your main throttle body are putting pressure on the throttle plate to open the door, then when you switch over to the cruise control, a second set of cables bypasses the original throttle control to control the throttle plate. This would cause a high idle undetected by the throttle position switch (as the door is opening correctly). The door would be open at idle, allowing air to enter the manifold, thus causing a high idle.

The fact that it engages harshly is kind of an indicator to me that your original throttle position may be off somewhat. You'll have to dig in and make sure of the position of your throttle cables, and that there's no tension on the way they are mounted.

Just something else to check, I guess.

Sounds confusing, I'll have to check my Bentley and see if there's a section on cruise control. Then again it might just be that it's crabby because it was originally from Quebec and I don't speak French.

Sounds confusing, I'll have to check my Bentley and see if there's a section on cruise control. Then again it might just be that it's crabby because it was originally from Quebec and I don't speak French.

You might be able to get away with a simple adjustment of the cables. They have plastic adjusters on them. Just take a look to see if anything is out of whack...