Hi, I've had similar problems recently with my 1995 Mk3. Engine always ticked over at 1,100 rpm when cold going down to about 300 rpm when at running temperature. For the last 5 - 6 weeks it started ticking over at 1,700 rpm when cold. I put this down to the recent cold weather but last Sunday, whilst driving in the rain, I put on the wipers and the engine began to cut out! (and the wipers would not function). I checked the wiper fuse (20A) and it had blown. Replaced it with a new fuse and it blew immediately. Left the car overnight and tried another fuse the next day and the wipers worked fine AND the cold idle speed was down to 1,100 rpm again. Surely a coincidence as I can't see how this could be affected by malfunctioning wind screen wipers.
The engine idled at 1,100 rpm when cold for almost a week and suddenly, yesterday morning, it went back up to 1,700 rpm.
I am totally baffled by this. The fuel consumption has obviously increased considerably and I don't know what to do to resolve this other than to take it to a Lexus main dealer and get a diagnostic test done (which will no doubt be expensive and may be difficult to detect as the problem seems to be intermittant).
Any chance it might be a problem with the air flow meter? Any advice welcome.
Cheers guys
Mick