stumble when first start driving cold

2002 XG350L with 42,000 miles has stumble when first strarting driving. Car starts fine, revs up, idle drops down then I put it in gear to drive. Car starts to bog as if it is going to die then takes off. This is every day lately. Once warmed up runs fine.

I have tried a bottle of CHevron's Techron but did not help.

Any ideas HyundaiTech?

Reply to
kr
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Dunno. If you've got a check engine lamp, you should start there.

But I'm presuming you don't. Try reinitializing the throttle: Turn the key on (don't start the car) and back off immediately and wait ten seconds. Your throttle will do a sweep.

Also do an idle learn. Start the car with the a/c on and let it reach operating temperature. Let it run for 10 more minutes. Then turn the a/c off and let it run for another ten minutes.

Reply to
hyundaitech

Is there any indication that the throttle sweep has been completed? Is there a beep or any dashboard light indication?

Matt

Reply to
Matt Whiting

Idle learn? Never heard of that. I did try the sweep but it didn't help. With the idle learn I just leave it idling the whole time?

Reply to
kr

Unfortunately, no. The only way you'd know for certain is to have someone listen or watch under the hood while you try to make it happen.

Reply to
hyundaitech

Yep, just leave it idling. It'll watch and learn where it needs to leave the throttle plate for proper idle rpm.

Reply to
hyundaitech

Is it safe to clean the throttle plate with cleaner? Engine running or not?

I know a lot of cars can be harmed if this is not done properly (ruin O2 sensors, remove coatings, set trouble codes, etc).

Also, thanks for all the assistance on here. Your feedback and advice is invaluable!

Reply to
kr

It's okay to clean the throttle plate with carb cleaner (while not running).

Reply to
hyundaitech

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