1983-1986
I don't have much researched out on this era
Engine is a 2.0L 2S-E
There was an option for a 1.9L Diesel 1CLC and in 86 a 2.0L turbo diesel 2C-T
1987-1991
Body style - 1987-1991
Updated engine 2.0L 3S-FE
Mostly unchanged for this year range.
1992-1993
First year Camry received the 2.2L 5S-FE engine
Body style - 1992-1996
1994-1995
California emissions got a new crank sensor pattern (24 point instead of 4 point) and also 4 injector channels instead of 2
Federal emissions mostly the same as 92-93
1996
Updated crank sensor design, on crank 36-2 pattern
1997-1999
Body style - 1997-2001
Ignition system rework, dropped the distributor for two smart coils in waste spark configuration
TPS updated design and connector, removal of the idle signal wire.
Engine Immobilizer became an option in 1998.
Fuel pressure and fuel system design reworked, pressure increased to 50psi and fuel pressure regulator moved from injector rail to fuel tank sending unit
2000 Fed Emissions
Same as 1997-1999 except computer connectors physically changed.
2000 California Emissions
Updated IAC design, instead of an open/close signal, it uses PWM to control how much to open it.
2001
Same as 2000 California Emissions
2002
Body style - 2002-2006
Updated engine to 2AZ-FE 2.4L with VVT
Coolant temp sensor connector inconsistent (2 pin vs 3 pin)
2003
Coolant temp sensor connector still inconsistent, but for this year the 2 pin meant it had an IAC and different computer logic to control it.
2004
Another year of split designs, PZEV effectively the same as 2003
Non-PZEV has an updated throttle body pinout.
All coolant temp sensors are standardized back to the 2 pin just like older cars had.
2005-2006
Throttle body pinout once again changed
Computer programming updated to require more signals to function correctly (harder to build a harness for).
Note: Injectors should always be matched to head and computer, fed emissions and cali emissions often times are different injectors that require different settings to work in the computer.