03 trail blazer ext. when going down the road from out of no where comes a loud grinding clicking metal on metal noise

SOURCE: Loud thumping noise in rear air

Hi, you should check if the blower plastic fan is rubbing against the fan housing ,they get lose with time and make those noises.good luck C1...

SOURCE: grinding noise while driving.

Possible causes:

a) a brake disc shield is too close to the disc, and it's coming into contact in the circumstances you outline

b) pebbles stuck between the disc shield and the disk

c) dried out wheel bearings

d) worn Universal Joints in the drive shafts

e) worn A/C pump

f) worn alternator

g) worn water pump

Is the noise still present above 15 miles an hour and past 1500 rpm when the clutch is disengaged (i.e. gearbox in neutral?). The answer to this question may help you to pinpoint the source. I know it's stating the obvious but the fact that you're hearing a grinding sound means it's caused by something that is moving relative to something else. Again this should help narrow down the cause.

SOURCE: The Key won't come why out the ignition in my 03 Chevy Blazer

Steering lock has came to rest applying pressure to key. Slowly rock steering wheel from left to right while turning key.

SOURCE: Vehicle cut off going down the road. The scan

Check the mass air flow sensor. Unplug it, then try to start the engine. If it starts and runs ok replace the sensor. Make sure the wiring is good to the sensor, The wires may break inside the covering near the connector ends.

SOURCE: 03 chevy blazer stalls when air is turned on

Sounds like your A/C compressor is seized up and stalls the engine through the belt train when the compressor clutch kicks in.

Try turning the compressor by hand (not from the pulley but from the front part (magnetic clutch), if you can't turn this by hand, it means the compressor is seized up...

As for fixing it, the actual fix would be to replace the compressor assembly, but believe me, that is usually not a cheap fix...
If you want the cheap fix, find the 2 wires that go to the compressor clutch (there is usually a plugin close to the compressor), unplug it and/or cut the wires and secure them to make sure they don't short out anywhere, or even better find the fuse for the A/C and take it out. Of course then the A/C won't work, but the clutch will not kick in and stall the engine...