what would this PO 340 a circuit mean? Replaced cam position sensor ,did not help

Question

2003 Toyota camary2.4 engine This car was running fine. She stopped at grocery store came out and it would not start. Scan for codes and got a PO 340 circuit A . Put a new cam sensor in did not help. Sometimes when cranking over it back fires out the exhaust. Need Help

Answer 1

P0340 Camshaft position sensor "A" circuit

Backfire out through the exhaust?  What set off this code condition are hard starting such as low fuel pressure , or a jump timing belt, (or timing chain)  or mechanical condition .Check the basic first such as fuel .