Throttle hesitation on 2000 I30

[bassa1]

Whenever I depress the throttle there is an hesitation before the rev picks up. At full rev the car runs fine. Problem is more apparent at start up. My first guess is some sort of a fuel problem, maybe the fuel pump. Air filter and spark plugs seems ok. Oh, I had recently changed the alternator. Do you guys have an idea of what the problem is?

[MaximA32]

IIRC, the I30's are an electronic throttle. Which means a signal has to go from the pedal to the throttle body saying, "OPEN HER UP!!" which results in a lag. The only way to have instant throttle response is to ride a bicycle.

Welcome to NICO!!

[bassa1]

The I30 is my wife's car, and I used to give her similar answers when she complains about, "a lag" or "a tug" on the car. I recently replaced a bad alternator, and when testing the car I notice the "lag", "tug", "hesitation" or loss of power, when accelerating. My wife swear I did something wrong when changing the alternator, because “the car didn’t this problem before”. I disconnected the battery, some connectors and the radiator when changing the alternator, so it's possible I may have caused this problem.The car definitely has a loss of power when the pedal is pressed for more acceleration. If I very slowly accelerate the problem does not occur but as soon as I press the accelerator the car it seems to struggle to pick up. The problem also occurs at inclines.

[maxhopper]

You may just need to clean the Idle Air Control Valve or the Mass Air Flow Sensor.

[generation2000]

I got the same problem. thought it might be the transmission but mayb enot , now that I read this. car has serious lag, especially between 1st and 2nd gear

[bassa1]

The MAF and air filter is clean, seems ok. I had started the car with the MAF connector unplugged so the 'Service Engine Soon' light came on, now I can't get the SES light to turn off. Does anyone know how to turn off the SES message on the 2000 I30?

Anyway, I finally got to really test the car today and I think it could be the transmission. When I gradually accelerate the problem doesn't occur, but when I push down hard on the accelerator, the car seem to slip into low gear and stay there, the rev remain constant. when I ease up on the accelerator the car seems to go into a higher gear. I hope I'm wrong, because transmission problems can be mighty expensive. My buddy told me it could just be a dirty filter. I would really appreciate any help from you guys.