shitbox

First off I want to say HAPPY NEW YEAR EVERYONE!

I have a question here regarding to my car during cold start.
Ok this happens whenever the car has been sitting there for hours in cold weather. When I start the car, the cranking sounds fine (i had my battery replaced a year ago), but once the engine starts to turn, the rpm would climb up from 0 - 500 and stays at 500 for like a second or two, the car shivers and the battery light comes on within these 2 seconds and then the rpm will slowly rise up to 1500 which is the normal rpm range when the car is not warmed up yet. Within those 2 seconds the car shivers really badly and I have a feeling that if the weather gets colder the car might die on me, which i will never want it to happen.

and then after i drove the car for awhile, when it reaches the normal operating temperature, whenever it comes to a stop, the rpm would drop down to 500 rpm and then rises back up to 800 rpm, it repeats for around 4 times and then it stays at 800rpm. (by the way my car is an AT and this usually happens when i have my AC on).

I don't know if those two problems are linked or not, and i dont know whats the problem of my car, if you guys have any clue or knows what's going on with my car, please let me know. Any help or any reply is greatly appreciated. Thanks and happy holiday!

offsight204

im having a almost the same problem. my car shivers when its real cold and it stops when the car heats up

slickrab

possibly its a frozen fuel line at warm up? Therefore the engine is not getting the right amount of fuel so it runs lean hence the zy increase/decrease in rpm.

shitbox

if its a frozen fuel line, would there be any way to prevent this from happening, i'm asking this because our coldest day of the year still have not arrived yet. I am afraid my car won't start in one of those days.

edit: i realized that i missed some information about my car, it's got 149,000km, running 89 and 91 octane(mostly 91), and replaced spark plugs 3 months ago.

poltergeist

What brand of plugs? I've seen Honda's that run like crap (esp. cold) with Bosch Platinum plugs installed. Even worse were the old "Split Fire" plugs that were "the craze" a few years back. Just swapping back to the OEM NGK's or ND's clears them up. Don't have a good reason why, but I've seen it on more than one car.

No matter what brand, you might want to remove and inspect the plugs carefully to make sure one doesn't have a cracked insulator.

shitbox

They are the factory recommanded NGK plugs, that's for the heads up and I will definitely remove and inspect the plugs sometime soon.

It is very cold today in toronto, it's around -15C in here and surprisingly it starts up very well without any shivering.

I will keep you guys updated

LukeaTron

Could be a sensor issue too. It sounds exactly like you're misfiring so there should almost definitely be a code thrown. If not, I would think the knock sensor would be suspect.

shitbox

check engine light never came on, i asked my mechanic friend and he suspects it might be a sensor faulty, but he said it's hard to locate which sensor though.

juzam2002

It might be the hydraulic engine mount that hasn't warmed up yet? Don't know. That oil needs time to warm up too i think. My friend has ahd the same thing happen. He said it wasn't really bad, just apperently noticable. my 2 cents

LukeaTron

With the RPMs dropping that low, he's probably not running on all 4 cylinders. This is going to be a lot easier to figure out with a full ECU diagnostic. Let the dealer monkey with it. I assume with that many "miles" you're out of warranty and it's probably not going to be super cheap to have tested but it's going to be a giant PITA to figure out any other way.