Three issues that popped up on my car recently that I think are related:
1. When starting the engine the "Wait for the glow plugs to warm up" light sometimes takes a very long time (10 seconds or more) to go out. This seems to be random and independent of outside temp or whether the engine is warmed up or not.
2. When starting the engine the revs sometimes shoot up to 2000rpm for an instant before settling down to idle. Again, seems to happen randomly.
3. The engine sometimes idles at around 1100rpm instead of the normal 900rpm. This happens most often just after start up and then disappears after a couple of minutes, but it sometimes re-occurs when the engine has been running for a while, for example, whilst stopped at traffic lights. Once again, there doesn't seem to be a pattern.
Any ideas? Is it some kind of dodgy temp sensor?