Why does my EVO stumble and bucks for the first minute of driving slow with partial throttle when the temps are cold outside(below 40 deg F).

The car is stock other than K&N air filter, but it does the same thing with stock air filter - already tried. I put on a grounding kit, makes no difference. I do not have any piggy backs's, reflashes, or anything like that done to the car. I have just under 5000 miles on the car.

The car is totally fine after a minute (even though it is not fully up to temps yet) and is fine if the temps are over 40 F overnight.

What gives? Whatever it is lame. I would expect such issues after modding it, but I do not have any.

 

I have the same issue. It almost feels like the 02 sensor is damaged for the first few minutes of cold driving.

I'm hoping it isn't an issue and just a "quirk" of the Evolutions.

 

my car behaves the same way. Anyone able to shed light on this topic?

 

Same here, I look like I am inept when someone first gets in the car with me on a cold morning. That first to second **** can be a neck snapper.

 

same thing with me.....my car does that when its cold outside...i think main thing is after turning the car on..let it warm us a little bit...and then start driving....

 

Warm that car up before taking off!!

It is tough if yoiu are in a hurry, but it is important because the car runs really rich..

Need to let it warm up first!!!!

 

I had the same problem with my fd, and my roommate experiences the same thing with his WRX. I am betting that the turbo takes extra time to spin up & get the oil flowing smoothly.... (I'm hardly a mechanical engineer, so take my opinion as only that)

I get into the habbit of changing CDs, taking out the garbage, whatever before I get going when the car is cold.

 

Didn't the dealer make you watch the little videotape and answer questions so they could market the Pit Pass to you???

It's not a direct quote, but close: "...let your Evo warm up for 2-3 minutes before driving it in colder temperatures..."

... yeah, right!

 

Well, in your owner's manual, it actually says to wait until you see some movement of the temp gauge before driving. I bet that's a good 3+ minutes when it's really cold out.

This morning was the coldest we've had this winter so far: 17degF. I was in a hurry, so even though I usually warm mine up for a minute or so, I just started it and drove off (very light throttle of course). My car didn't stumble at all. It may be a common thing for EVO's, but it's definitely not on ALL of them.

 

Trigeek37: I don't think it is turbo related... we are not boosting at all at these times. It's the putting around in and out of your driveway & street at 10 mph sort of thing...

Yeah... let it warm up. I'll give that a try. I was taught that it is better to putt around while the car is warming up as opposed to letting it sit and idle. Forgot what the theory behind that method was, but it might have something to do with the car warming up faster and therefore getting the oil into its operating range faster. I just don't remember - sorry.

Thanks..

 

people....u guys have to start using 5w30 motor oil....its for the cold weather....10w30 is for warm weather

 

I noticed this with my Evo also though it can be subtle. There's a hill about 1/2 mile from my house and on cold mornings, I can feel the hestiation/stumbling ever so slightly while going up this hill. This tells me that the problem is boost related since I stay out of the boost otherwise until the engine warms up completely.

My 97 Talon did the same thing in the final Winter that I drove it. I had a boost gauge and when it got around 10 psi, I would feel the stumbling. After a few minutes, it wouldn't happen anymore. I tested the engine and found several boost leaks around 8 psi. I fixed them and the problem went away immediately.

My guess is that the colder temps make the gaskets, hoses, etc contract and leak under partial boost. Once things warm up, there are fewer/no leaks due to better sealing. I plan on testing for boost leaks on my Evo when I install a boost guage.

 

this has been discussed before. if i remember right you need to let your car warm up because your ecu is running a different loop. the car runs really rich to let the catalytic converters heat up. this is for better emissions.

 

Just let the engine warm up a bit. Not a big deal as everyone else has stated.

 

The car is going to run in open loop (default setting) until the O2 sensors reach 600deg. I think thats right. somewhere around there. I always wait till the temp. needle moves off the C to the bottom notch before I go anywhere. Never have this problem.