This morning I tried changing the warm-up regulator and the result was the same - when cold the engine idles too low (around 400 to 500 rpm). I found, when changing the brake master cylinder the other day (see the page at "
After changing the warm-up regulator I decided to pull off the small vacuum host from the same connector that the larger hose from the brake booster attaches to and found that the engine revs increased to exactly the right area between 800 and 900 rpm.
I don't think this conclusively proves what the cause is, but it more or less confirms that the problem is vacuum-related so I'll be putting the original warm-up regulator back into the car tomorrow.
I'm beginning to think the problem is related to vacuum hoses connecting directly to the throttle valve, though if any of you have some suggestions I'd happily take them on board and see if they bring up any new leads. I am trying to avoid dis-assembling the dash to see if the mis-connected hoses on the climate-control selector are the culprit since pulling the dash apart is a major job. 8-)
Regards,
Craig.