I have a problem starting it only now that it is cold outside

KSWISS3978

MEMBER
2003 NISSAN ALTIMA
4 CYL
FWD
AUTOMATIC
57,000 MILES

Hi, I have a 2003 Nissan Altima 2.5s. I have a problem starting it only now that it is cold outside. When the car has been sitting around overnight or for 8 hours while im at work is when my problem accurs. When I start it, it will run very rough for a few seconds, the rpm's surge wildly between 500 - 1100rpm, then cut off. To keep it from cutting out I have to tap the gas pedal in time with the surges so the rpm does not drop too low. I have to give it about 5 taps so that it will stay running. But, after that it runs rough for another minute and tries to keep the idle around 600 or so. Other than that the car is fine.
I am thinking that maybe one of the sensors is not reading that it is cold outside and is not telling the computer to fast idle until the engine is warm.
I find it strange that the fans come on even when the car is cold. Maybe the computer is getting a signal that says the outside temp is warm or hot.
Please help. Thanks in advance.

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Check the coolant temperature and throttle position sensor. The CTS demands fuel enrichment during initial cold starts meaning the computer will increase the injection duration till it goes in closed loop at this time the oxygen sensors controls the air/fuel mixture. This sounds like the crankshaft angle sensor or the fuel pump has gone out, when you turn the key to the on position without cranking the engine over can you hear the fuel pump run in the tank for 5 seconds? These guides should help us fix it.

https://youtu.be/dCjmRL3p4Cs

and

https://www.2carpros.com/articles/car-cranks-but-wont-start

Also, lets run the codes to see what come up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down these guides and report back.