I have a ford mustang 1999

Question

I need to know if it is safe to drive it if it has all those codes

Answer 1

P0171 Fuel trim lean Bank 1

P0340 Camshaft position sensor circuit malfunction

P1390 Octane adjuster

P1000 Monitor testing not complete

What you have is a lean fuel trim this mean you have more air than fuel you may experience a rough idle , and in the mix with this a P0340 this can also be caused by a hard to start condition or excessive cranking. or a failed cam position sensor , with a failed cam position sensor you can stall out at idle. With P1390 this is the octane bar you get this code condition when the octane bar has been removed.P1000 is when the CK ENG LT has been recently cleared. Because of 2 code condition P0340 and P0171 it is  better you resolve these 2  condition. You can do more damage, The purpose of the CK ENG LT is to protect the catalytic convertor and catalytic is to protect the enviroment.With the CK ENG LT on you can damage the catalytic convertor . So you should not drive it.