Skip the auto shop - Our mechanics make house calls

Q: Hard to start when engine is cold

asked by on

It had a code p0403 Egr issue. I replaced the egr valve and transducer but it didn't fix it. Sometimes it will start right up other times, it turns over great and tries to start then when I open the throttle it will finally start. It runs rough until it starts warming up then it smoothes out and if I shut it off it will start right back up if the engine is warm and runs great. I also have a code that shows o2 sensor bank 1 sensor 1 is shorted but I have not changed it yet. It feels like it lacks power so I believe the catalytic converter is bad. A temperature measurement on the inlet side shows 550 degrees and on the outlet side is 500 degrees. because of the rough idle issue when it is cold I recently cleaned the throttle with brake cleaner sprayed on a rag and sprayed the maf sensor with an aerosol electronics cleaner. Thanks...

My car has 150000 miles.
My car has an automatic transmission.

Hi there. It is possible that the O2 sensors are causing the hard starting problem. It’s also very common for a cold start injector or the radiator coolant temperature sensor to cause cold weather starting problems as well. I would check those components for operation and connectivity and replace if needed. If you still can’t find the source of your cold starting issue, contact a professional mobile mechanic to complete a car is hard to start inspection.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 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!

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: serious issue with my right rear brake.

Yes, I agree this is a serious issue. If the hub bearing failed, the tire and brake assembly would be loose. To check this, raise that part of car off the ground, put hands on each side of the tire...

Q: My timing belt broke while idelin an in park. Could there be damage to the vavles

The 2.4 is supposed to be an interference motor but there is a chance you did not damage the engine. After installing the new timing belt you need to do a compression test to make sure you did not bend...

Q: How much will It coast to have theft lock took off car

Hi there: Sorry but this is not a service that we provide at YourMechanic.com.

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.