Need code definition for ford thunderbird 96. codes are p0135,p0155,p0304,p0172........obd2

The only codes on your car that are only Ford codes are the one ranging in the 1000,s your codes start with 0,s there fore they are generic OBD2 codes
P0135=O2 Sensor Heater Circuit
P0155=O2 Sensor Heater Circuit
P0304=Cylinder 4 Misfire Detected
P0172=System Too Rich

A code P0135 may mean that one or more of the following has happened on Bank 1, Sensor 1:
•O2 Heater element resistance is high
•Internal short or open in the heater element
•O2 heater circuit wiring high resistance
•open or short to ground in the wiring harness

Possible Solutions:
•Repair short or open or high resistance in wiring harness or harness connectors
•Replace oxygen sensor (cannot repair open or short that occurs internally to sensor)

A code P0155 is same issue as above only it affects Bank 2, Sensor 1

A code P0172 basically means that an oxygen sensor in Bank 1 detected a rich condition (too little oxygen in the exhaust).

Possible solutions include:

Inspect all vacuum and PCV hoses, replace if necessary
Clean the MAF sensor. Consult your service manual for its location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect fuel lines for cracks, leaks, or pinches
Check the fuel pressure at the fuel rail
Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

A code P0304 simply means a misfire was detect on cylinder #4