Q: Hard to start stalls out

asked by on

Truck won't start unless I hold the accelerator all the way down one started will Idol when you try to accelerate it tries to stall out

My car has 3000000 miles.
My car has an automatic transmission.

Hi There, As a general rule, car engines do not like cold weather and do not do operate as well in cold weather. When you start your car in the morning and turn the key to on, the coolant temperature sensor immediately reads the temperature of the coolant and relays this to the computer indicating that the coolant is cold. The computer then knows at this point that it needs to enrich (add more fuel) the air/fuel mixture at startup due to the change in air density. When you start the car, you will notice that it idles high for a period of time until the engine warms up. This is the enrichment cold start process.

On older carburetor engines, you pressed the gas pedal before starting to set the choke position and give a squirt of fuel into the engine via the accelerator pump. This was necessary because the carburetor does not feed fuel as efficiently as a fuel injection system does at low (starting) RPM. A cold engine also needs a little extra fuel to compensate for lower vaporization at low temperatures. The fuel injection system does nothing until the engine is turning (starting or running), so pressing the pedal before you start will make no difference. The fuel injectors work at any RPM, so a choke is not necessary. The computer simply feeds a little extra gas through the fuel injectors to start the engine. Cold temperature fuel delivery is also managed by the computer which checks the mixture with oxygen sensors. With that said, it is likely that you may have an issue with a faulty oxygen sensor which is what provides feedback to the engine after it starts as exhaust gases flow through the catalytic converter and past the oxygen sensors. I would recommend having an expert from YourMechanic come to your location to diagnose your oxygen sensors and cold start.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Hard to start stalls out

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: What causes vehicle information center to turn off?

Hi there. There are typically three issues that cause the display to fail; a blown fuse, damaged electrical relay or a fault in the ECU. To determine which one is causing your failure, it's best to have a professional mobile...

Q: Need AC temperature actuator replaced.

Hi there, AC blowing cold from some vents while warming up in other vents may be an indication of a low refrigerant charge level. This is what is likely happening due to low refrigerant level: The air passing over the...

Q: 2wd 93 suburban from start off quickly there's a jerk binding feeling I'm in rear end other then that she rides smooth any idea

If the problem is literally isolated to the rear (versus the transmission or engine), it's either the brakes sticking, the differential, wheel bearings, or other part interference of some sort. To have the exact cause determined, the vehicle will have...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.