Hi there,

We had some unseasonably warm weather (80's) for about a week and I noticed that when aggressively pressing the accelerator that the response was lagging. Then about a week later the temps cooled off (65F-70F) and I had the immediate response back. What would be causing this?? Would it be like a variation of vapour lock???? The vehicle has about 70K kms (45K miles)

Both of our 2002 Elantra VE's are dealer maintained

 

I am assuming this is on your Elantra. We do haave a refalsh for the pcm for hesitation during initial cold start in morning. Does it happen just in the morning or all the time?

 

Yes, this happened on my Elantra and no it is not just at startup but after running for a while. When driving, I "mashed" down the accellerator during this hot weather and the quick response was not there. However, a week later during colder weather, the problem seemed to go away. The car started well, but that response was not there during the whole drive in the hot weather. However, the day it cooled off, the response was there all day.

 

I would have the dealer reflash for the cold /warm ambient temp stumble. I would also have scan tool put on it to ck for any codes stored. If no codes are stored I would do a re-learn. To do this you basically disconnect the negative for about 10 minutes. Reconnect it, drive the car with about 1/4 accelerator pedal through all 4 gears . Drive like this about 2 or 3 times. Then drive the car normally like you would. This allows the TCM to relearn your driving habits and settles alot of trans shifting issues.

 

Just a thought .....But I would check your radiator temp at driving conditions during warm trend.....if it tends to climb and stay at 210 degrees or more ya could have a flow concern wich makes the car lean out and show noticablepower loss .....when the car is cooler it tends to run fatter thus giving it more fuel and timing..........the vehicle should be checked for long and short fuel trim under both conditions to see if there really is a concern and where the concern lies[sm=insomnia.gif]

 

saugen48,what octane are you filling ?? If it is 87, then fill a higher octan on hot temp season, then the ignition timing will not retard so much !!!

REMEMBER, the owners manual states:
MINIMUM 87 octane OR HIGHER is recommended !!!!!!!!!!!!!!!!!

 

Basically what it boils down to is bring it to a shop and have someone evaluate if any codes are present and diagnose the vehicle properly. Duke I agree about the octane. As for the radiator temp reading above normal then the a/c compressor would cut out and he would be complaining about that also.

 

I should have mentioned that both vehicles are automatics. Both vehicles have run famously on regular gasoline since we got them two years ago. Never have I experienced this lag in warm weather on either car before. There has never been any check engine lite either. Thanks for all the help.
It is due for the 72K checkup pretty soon, so, if problem persists, will have the dealership check for codes etc at that time.
Thanks for all the response.

 

I had a similar problem this weekend, vehicle is a Santa Fe 2009. Very hot external temp 112F, air on medium, temp gauge below half point, climbing medium grade, gas quarter tank suddenly lost power. Pulled over shut everything down waited for aprox three minutes, vehicle started OK, nothing since then. I thought vapour lock was a thing of the past?

 

Radiator fan issue?

I have found out Rad fans on Hyundai's don't come on until it's really hot or the A/C is on. The engines are tightly packed and heat up quickly once you turn the car off, it is strange that Hyundai doesn't have cooling fans engage without the key in the ignition and they rarely come on during idling after running hot (bad engineering design in my opinion) I almost wonder if all Hyundai's suffer from too much heat and that added heat wears things out faster than norm.