Skip the auto shop - Our mechanics make house calls

Q: When cold the car misses. Later in the day it runs good. This is a new car to me recently purchased. Morning temps are mid 40's

asked by on

When I fist start and run the car in the morning it missed alot. Later in the day it it runs very good.

My car has 156000 miles.
My car has an automatic transmission.

Hello there, many different faults can cause your 2004 Hyundai Santa Fe to run poorly when cold. The most likely faults would be a stuck open thermostat, coolant temperature sensor, oxygen sensor, vacuum leak, or exhaust leak. A qualified technician from YourMechanic will be able to diagnose your rough running when cold issue and make any repairs required.

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
  • Home
  • Questions
  • When cold the car misses. Later in the day it runs good. This is a new car to me recently purchased. Morning temps are mid 40's

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: Overheating, mostly when car is not going forward

Hello, thanks for writing in. If the fans are not coming on then it may be possible that the fan switch or fan relay are bad. I would test them to see if either of them need to be replaced....

Q: Bad turn signals

Hello. This happens al lot on this vehicle. The problem is typically the turn signal switch assembly. The switch contact fail internally and cause this to happen. I typically check the voltage at the switch first to verify that it...

Q: Where Is the O2 Sensor Located?

Oxygen sensors O2 sensors will always be located in the exhaust system. Their function is to sense how much oxygen remains in the exhaust that is flowing out of the engine, and report that information to the vehicle’s engine control...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...