Hard Starting Engine



My 2000 S-10 pickup, 4cyl.,starts like a whiz at 10 below zero. But I can go out at 40 deg. start it up drive it a couple of miles shut it off. Come back a half hour later and sometimes I have to put the gas pedal all the way to the floor to get it to start. Yes I know its fuel injected.

Any reasons of ideas?


In fuel injected engines, when you press the gas pedal to the floor, the engine computer cuts fuel injection off completely. So, you are leaning the engine by pressing the gas pedal down.
The fuel flow might be too rich, when the air temperature (and engine) is warmer. HOW could the engine be too rich? The engine coolant temperature sensor could be faulty, and the engine computer would respond by commanding more fuel injection. The Fuel injectors could be bleeding down, after the engine is shut down. This would dump fuel into the intake manifold. The idle air control valve might be stuck closed.
Now, what? Use a Throttle Body Cleaner to clean the air intake tract, the idle air control valve, and the throttle bore and throttle plate. Also, use an MAF Sensor, since you’re in the intake tube, anyway.
To check for fuel injector bleed-down, attach a fuel pressure gauge to the fuel line, and watch it for a few minuets after the engine is shut off. The fuel pressure should stay up for minuets, or hours. If it doesn’t, the fuel injectors might be leaking down, or the fuel pressure regulator is releasing the fuel pressure. It shouldn’t.


Thank you hellokit. I kn ow little of these new cars and trucks. Was weaned on plugs, points, carborators etc.