Engine wont start, unless I push the gas pedal and keep my foot on it.?

SOURCE: 1989 4cyl 4x4 Isuzu "Space Cab" truck won't start in cold.

yes

SOURCE: RX300 Engine Stalls when I take foot off the gas pedal.

The Idle Air Control (IAC) valve is clogged. This part feeds air to the engine at start-up and idle when the throttle bodies are closed. I removed the throttle body assembly from my 2001 RX300 and separated it from the IAC. After a good cleaning with throttle body cleaner the IAC was good as new. I later decided to replace it during routine maintenance. You can pick up a brand new IAC on eBay (genuine Lexus/Toyota part). The dealer will want upwards of $400.00 for a 45 minute job (all you need are basis hand tools).

SOURCE: wont hold idle will start with foot depressing gas pedal will run with foot on gas but stalls when foot removed

Check and clean Idle air control valve. Make sure its responding to signal as well. Also make sure ther are no vacuum hoses disconnected. This may not be a "cure" but it's a good place to start.

SOURCE: Car is not idling. Need to keep foot on the gas pedal to start.

Hi there,
there is a screw(situated in a hole) on the throttle body and this can be adjusted to increase the rpm. anticlock to raise the rpm.

SOURCE: won't start unless you push

it sounds like fuel pump is going. pressure should be around 40 psi.
Or it could be flooding. Holding gas pedal to floor during cranking of the engine, shuts off fuel flow through the injectors to clear a flooded engine. After engine is running again, it lets fuel flow.

If you have a Mass Air Flow Sensor in the iar intake tube, clean it with spray carb cleaner several times.

Also, try disconnecting the oxygen sensor to see if it helps. It will turn your check engine light on, but you can cycle key from off to "on" 40 times to turn it off.