2001 triton 5.4 warm but will not idle or when its cold

clean throttle body,and check for vac leak

Sounds like a coolant sensor problem. It signals the ECU for open loop, cold start rich, high idle, until warm up is reached.

spark plugs good

When the engine and oil are cold it will show a high pressure because of the viscosity of the oil. When it warms up the oil is thinner. If it doesn't drop below 20-25 psi at warm idle I wouldn't worry about it as that is normal.

vacuum line cracked or lose

full power is only achieved when the engine is fully warm(operating temp).so if you accelerate more than, say, a third of the gas pedal,the car will feel sluggish.
this is more apparent when first starting the car in the morning in winter.almost like the car is going to stall.
most wear in the engine is leaving it to idle when cold you should always drive the car straight away from cold.then when hot turn on the a/c if required....

the idle air control valve may be bad or just needs cleaned out. idle air control valve acts the same as a choke. if it is messing up it will cause engine not to run right.

sounds like the idle air control motor.typical symtoms for this motor is rough idle when cold.

Seems like an idle speed control to me.

have it scanned,ck' tps sensor,mass air sensor,idle air sensor for output...kev-mn.