I have a '05 Evo RS, around 15k on it.

On cold or cool mornings like 40-50 degrees i get lots of hesitation and stumbling when i try to take off. Idle is fine. Once the clutch is disengaged and I am moving, if i apply throttle it hesitates real bad. A few minutes later it runs like a champ. If it sits say until lunch the same thing will occur. Now if I let it idle and warm up for 2-5 minutes I dont get this problem. Its really started now that fall has hit.

I know its the not the clutch slipping. I run 92 octane. Could it be bad gas, i get the gas at the same place usually? Dirty injectors? Dealer is 2-3 hours depending which one i go to, going to see them if i dont get it sorted out. I figure they will have it stay overnight, start it, warm up, oh no problems, good to go.

Any ideas? Or similar issues?

 

i have the same issues...i would like to know what it is

 

you need to let your car warm up before getting on the turbo. Make sure the temp gauge is normally where it sits after driving and you should be fine. From what I hear EVO"s dont really like cold weather....Just imagine drivining it in 0 degree temps!!!

 

let the car warm up. cold evos jump and lerch all over the place. not uncommon at all. i think it has something to do with cold turbos in general. try not to drive the evo cold if possible. if you have to roll out, keep your revs low until she warms up a bit.

 

Some dry gas couldn't hurt. It's that time of year. Lot's of condensation!

 

under colder engine temps, the ecu must provide the engine with a greater supply of fuel than operating temp. this accounts for a rich warmup.
this is normal for any car.
as stated above, it is best to wait for the car to reach operating temps, before running it hard.

hope this helps.

Ken

 

they all do that, let your car warm up before u drive it, you are suppose to do that anyways

 

This is normal. My car did it when it was stock and still does it now. I usually try to let my car warm up for at least 2 or 3 minutes, but if I'm running late I just make sure I'm real easy on it and shift very early. It's nothing to worry about.

-Paul

 

Mine doesn’t hesitate on cold mornings or when cold.

 

mine did not do it...then I got and AEM and it started to do it...changed to a flash...and it did it. AEM probably had nothing to do with it but who knows. I think it is the engine getting too much fuel(rich warm up conditions)...then trying to catch up by leaning itself out and you get that hesitation...like the car 'gives up' for a second...then gets going.

 

Yeah, from what I have heard, alot of evos do this, they dont like cold starts, just do what you have been doing before you start driving, whichis let it warm up for a few minutes.

 

sounds like MOST of us have the same issues. mine might be more exaggerated right now due to condensation in the tanks @ the stations. dont think its a cold turbo thing, ive had lots of turbocharged cars, never had this issues happen. guess a heated garage would be nice...but i'll just go with warming up.

i wonder what is causing it to do this. to much fuel, lack of compression?

are all fuel treatments created equal? any recommendations?

 

The problem is more a lean condition then rich. The O2 sensors are heated so they come up to operation temperature pretty quick. At the same time the car can go into closed loop at around 50 degrees farenheit which is way too cold for the ECU to be trying for 14.7. Everytime you shift the engine goes lean and does not recover quick enough to avoid falling on it's face in the next gear.
This is very difficult thing to work around. We managed to improve this alot on my car but as it gets colder it still exists, but my car is difficult to tune around in it's current state.
AEM can be tuned to stop this situation entirely and honest that is the direction I am heading once I have the money to do so.