Car stalling when cold. Always rough start.
 

I bought my S2000 about 1 month ago. It had a little problem when starting up since I got it. It did not seem like anything when I test drove it but seems be getting a little bit worse. Probably due to the cold weather where I live.
When I start it, the rpm's always drop down pretty low and make the car shudder a little bit. Once in a while when it has been sitting for some hours in the cold I'll go to start it and it will drop too low and then just stall out. That happened tonight and then I went to start it again and it took a good 5 seconds or so for it to turn over and start.
I searched a little bit on here and everyone said the ecu will "learn" and adjust the fuel next time. This has not seemed to have happened as of yet. It has stalled maybe 6 times since I have had the car, but basically always even when warm will shutter a little bit when starting it up.
Usually when starting it the rpm's will shoot up to like 2500 and then drop down to around 400 or so and shutter and then back up to 2000 until it warms up and then normal.
Is there something in particular I should check for?
Also on start up the engine makes a loud scrape/rattle sound. I think from researching on here it sounds like it might be the timing chain tensioner. Is that something that it could do when loose or bad?
Any advice would be very helpful.

My car does that sometimes too. Even if the car is in neutral, it feels like it is starting to stall but it's not that often. I can't remember if it was necessarily in the cold or not but I dunno if it means anything bad. I have an 05 by the way.

this problem usually appears on early models AP1. becoz the flywheel on the AP1 is very light compare to AP2s. a little shuttle is normal but definitely will not stall out the car. If u hv stalled about 6 times in a month , u should bring it to the dealer or a mechanic for a check up, change the engine oil. check for valve bends or cracked retainers, or maybe a loose clutch too. :)

I would do 4 things right away if I had this problem.
1. Change the air filter.
2. Clean the throttle body.
3. Change the spark plugs.
4. Change the PCV valve.
In other words, give it a good tune-up!
Good luck.

Maybe also check to see if you're on the original battery.

:iagree:

And since you (the OP) is a member of the NY Metro crew, run your problems by Billman250.

OK I'll take a look at those things. I am on the waiting list for Billman right now so when that comes available I can have him check it up if I don't figure it out first.
In regards to the battery how would that cause it to stall out once it turned over and started? I don't see how that could affect idle once it was running.

In regards to cleaning the throttle body is that an easy task?
Do people run sea foam through their car ever? Mine is an earlier car and has over 70k on it so should that be done?

mine does that to if its really cold and i haven't started it in a while but always fires right up the second time

Yeah mine until yesterday always fired up the second time. Yesterday was the first time where it took a few seconds for it to start. Thats what made me a little more worried about it.