The car is a 2002 Sonata with the V6 engine. 70,000 miles. I recently noticed( my wife's car) that in the morning, the engine seems to crank a little bit longer than it used to. This does not happen if it sits for an hour or 2. She hasn't noticed it yet and doubt she ever will. The engine light came on yesterday and when I got home, I hooked a scan tool to it and there were no codes. Is there anything that sticks out on these models that could contribute to this? The plugs have been in for 15,000 miles and the timing belt was replaced at 60,000. Thanks in advance.

 

The first thing that comes to mind is the vapor canister purge valve.

 

Usually the CEL (check engine light) comes on if there is a fault detected.
And it should have a DTC (diagnostic trouble codes)
If the light goes out then it means the problem stopped for the moment.
Like when my ABS sensor was intermittent, the CEL would come one and then go out.
But, it always logged a DTC.

There is the transmission control module which most simple scanners don't communicate with.
When it makes the CEL come on, it might not show up on your regular DTC.

Hmm, extended crank time?
Could be many things .. but the one that comes to mind is a leaky valve or injector
So that when it sits overnight, the fuel goes into the cylinder causing a flood condition and an empty fuel rail
Don't really know. Just guessing.

Good luck and please up date what you do to find and resolve your situation, thanks

 

Is there a way to test it? Where is it located?

 

I forgot to add that when it does start-it does not miss or run rough. Runs normal.

 

On my Elantra 2001, it is located on the driver's side behind the rear wheel.
I would assume it would be in a similar space.


Yeah, a slow leak like that wouldn't make the car run rough or miss
Just make the car crank for an extended period of time on initial over night start up.
But, there are many things that would do that too.