Got a very temperature specific problem. 94 Camry, 4 cyl. automatic, 173K miles. When car hasn't run for several hours, it starts fine, every time. After reaching normal temp (it never overheats), car must be held above 1200 or so rpm when slowing and stopping or engine may die. If it dies, it won't start until it has cooled down to nearly ambient temp. In warmer months this cool down period can be 40 minutes or more. If left alone for several hours, it starts normally.

Occasionally, idle speed hangs at 2000 rpm. If car is turned off when this is occurring, it won't start again until it has cooled down.

Starter works normally, but engine won't fire until it has cooled into its comfort zone. When car is refusing to start, I can smell gas, so I don't think fuel pump is problem. I bought car with 134K miles and drove it 3 years with no problem. I have replaced plugs, plug wires, air filter, rotor cap, coil, & pcv valve. Anybody got a suggestion?

 

Under the throttle body is the Intake Air Control valve (IAC). The valve controls engine idle and can cause hot start problems.

The valve may need of cleaning. A Google search with turn up lots of hits on cleaning the valve. Basically this involves removing the air intake hose, spraying a throttle body cleaning into the valve port with engine running. Use a cleaner that is converter, O2 and plastic safe, the valve is made of plastic.

Some folks remove the valve to clean it.

Might also be the fuel pressure regulator and check to make sure the engine has spark when cranking.

 

If cleaning the IAC does not resolve your problem you may have some engine flooding related to the engine coolant temp sensor (not the one located on the bottom of the rad). You will need an ohm meter to test resistance at specific tempature.