Idle down when clutch in?
I am new to the forum, have browsed a little bit while researching what type of truck to buy.
Tonight I just test drove a 2000 F250 7.3l, 6 speed manual, 4wd, 2"lift, rancho shocks, with 64k on the odometer, power locks, power windows, cd player, sliding window, bed mat, bed cover. It's got a clean car fax history with a recent service by ford @ 55k. The body has absolutely no rust or damage, the frame has a little bit of surface rust in a couple of places, I am not surprised with it being 10 years old. I've put a deposit down as they are only asking 15k. I plan on having it put on a lift and checked out, the main thing I will be looking for is leak from rear main seal and cracked manifold bolts among other things.
Anyways to get to the point of my post...
When I first started the truck after about 30 seconds the idle went up. Let it warm for about 5 minutes and the idle stayed consistent the entire time. As soon as I pushed the clutch in the truck idled down. Again it stayed consistent the entire time I drove it, when pulling to lights etc. I pulled off the side of the road to engage 4 wheel low, put the parking brake on let out the clutch and it began to idle up. As soon as I pressed the clutch in it idled down. Is this normal? I am thinking they designed it this way to prevent build up of carbon from low idle speeds?
Thanks for your help!