2006 elantra Auto1.8 stalling when engine is warm and hesitates when gas is pressed, also sudden loss of power?

Question

I have changed the spark plugs and it is still the same. Once i have cleaned the throttle body, the car didn't stall for few days. After that it is still the same. It only happens when the engine is warm, and the car has this kind of lag/ hesitates when the gas pedal is pressed, Like when i'm going up the hill, the car struggles to change to a lower gear and the car starts to shake a little, i have to press the gas more than usual just to force the car to change to a lower gear. also it takes more than 2k rpm just to change to a higher gear. I have driven a new vios and it didn't need 2.5k in shifting gears.

I don't know if it is normal, but at night when the lights are on, gas pedal pressed, the light seem to be brighter. When i release the gas it goes slightly dim.

fuel economy is also less and the sound from the exhaust too sounded a bit harsh than normal. I have sent for an ecu check before for error codes but nothing serious, the mechanic set it back to normal and i got a smooth idling again, although the stalling never ended. I happens when im accelerating, i press the pedal at half, then as i release to a quarter, the car starts losing power and if i don't give more gas i dies. This happens sometimes when i'm driving after more than 10 minutes or so and when the engine is at operating temperature. Also i am driving in a hot country where it is always about 32 degrees Celsius day.

there are no black smokes of any sorts and i have check with the mechanic and they said that my elantra doesn't have a fuel pump? or is it that they looked in the wrong place?

this car has about 185,000 km mileage

my thinking is that either its

ignition coil,
bad throttle body sensor with its dirty throttle body.
or it could just be a bad fuel pump - as my car only starts stalling when the engine is hot. and sluggish on the hills.

Answer 1

It sounds like it could be the catalytic converter is starting to get blocked and is not letting the exhaust out. I have seen this many times. Have a shop check it out. You can also drill a small hole in exhaust pipe just before the converter and just past the converter and check for the pressure difference between the two while the engine is running. Should be little to no difference.

Answer 2

I agree, when the converter starts heating up the particulates swell and block the passages. The amount of mileage is about right for the converters lifetime also. If you cannot let the exhaust out the engine cannot take fresh air in.

Answer 3

Stop guessing and nail it down with an OBD 2 code check. My guess is a vacuum leak. You want to be sure before you spend a lot of time and money replacing stuff that doesn't need replacing. OBD2.

Answer 4

You're off to a good start by cleaning your throttle body but your car probably needs a little more cleanup.



Clean and test the following components and see if this won't clear up your problem:



Exhaust Gas Recirculation Valve



Idle Air Control Valve



Positive Crankcase Ventilation Valve



See procedures below: