2.3 1990 Mustang Hard to start

[Darkshadow90]

My 1990 2.3 seems to be starting very weridly i have to just keep turning it over for it to fire and it shots carbon out the exhaust but once it starts its 100% fine from a cold start the car seems to fire right up but when its hot it seems to take a while anyone have any idea of whats wrong?

 

[72COMETGT]

There could be a number of different things wrong. I need more info.
Like- how does the car crank, very slow, slow or normal. Does it fire, sort of fire and then stumble or not fire at all. Will it eventually start by constantly cranking it and then it fires.

I need to know what its doing when you try to start it. Like after the car sits over night. When the car has already started but engine is still cold/cool and you try to restart it. When the car is hot/normal running temperature.

 

[Darkshadow90]

It starts kinda slow but itll fire then go from 500 rpm to 600 rpm then itll go to normal and whens its cool when i shut it off itll start up fine but then die if i dont rev it a bit then after a while everything is fine but now. when im driving my Check engine light will go on and my car will slow down a bit like the rpms will drop 500 and then go back to being fine

 

[72COMETGT]

So it sounds like it cranks fine when you turn the key to start it. Or close to it. The things I would look at are.

Fuel pressure- should be around 30-35psi at idle. Around 45psi with the vacuum line disconnected from the pressure regulator. Could be the fuel pump or the pressure regulator.

Throttle Position Sensor- could be worn out and the voltage signal the the ECM reads could be out of range or intermittent . Around .80 volts @ idle and 5.0 volts @ wide open throttle. Could cause CHECK ENGINE light.

Oxygen sensor- Out of operating range or not working at all. Could cause CHECK ENGINE light.

Catalytic convertor- might be starting to clog up/melt down causing the engine to be choked off with no exhaust flow.

Throttle body & Idle speed control motor- Make sure they are clean. They should be removed and cleaned periodically. This could cause a hard start issue and a idling problem. This should only affect the idle or throttle hesitation when you press the gas pedal. Should not affect cruising speed drivability.