Throttle Sticking?

[JerryB52]

Just today, I was coming to a stop light in traffic and when I tried to apply the brake, it (the Brake) seemed very stiff and the engine did not throttle down! I immediately threw it in N so that I wouldn't hit the car in front of me. Then it throttled down.
Anyone else have this happen? It did it again before I got home at a stop sign.
2 or 3 weeks ago this happened just once and I thought I may have accidently knocked the shifter into the sport shift mode. Now I know it's something else.
TPS sensor???

 

[Mark_888]

I think you need to take it to a dealer and see if they can replicate it. I know that dealer repairs are not cheap (if your warranty has run out), but that is a serious safety issue.

 

[JerryB52]

I agree. If I wouldn't have thrown it in N right away, I would have caused an accident.
I called the dealer and they will take it in tomorrow morning. In the mean-time it is going to stay in the driveway.

I hope they can figure it out and hope it won't be too costly (I'm retired, fixed income).
This dealership has been good to me so not to worry...

 

[dougmcp]

I'd be suspect of the throttle position sensor. Have you had any CEL's? This may deserve a call to your dealer for an initial consultation.

 

[JerryB52]

Took my Genesis to the dealership yesterday and dropped it off my.
They called me a few hours later and said after two different test drives, they could not get it to duplicate the problem.
Scanned for codes, none found, inspect brakes, front at 5mm and rear at 6mm. Ok
It cost me $81.96.

To me, it's almost like there's air in the brake lines... Maybe this weekend I'll bleed them.

 

[Mark_888]

To me, it's almost like there's air in the brake lines... Maybe this weekend I'll bleed them.

I am not sure that is a DIY job on the Genesis. I believe dealers use a computer hooked up the HECU to do that.

 

[JerryB52]

Okay. Update. Same thing happened twice today. Began to brake and it throttled up. Again I had to put it in neutral to stop in time. It revved up to 4k rpm when I put it in neutral then ideled down. A friend of mine suggested try WD40 on throttle body linkage. But when I looked under there there is no linkage that I can see. I squirted just a small amount of WD on the butterfly inside the throttle body. As mentioned above it may be the throttle position sensor.

 

[Gunkk]

Almost sounds like the cruise control not disengaging, trying to maintain speed while you're slowing down. Check to make sure your brake lights light up when you hit the brake pedal (check for faulty brake switch). What year/trim is your car? Smart Cruise enabled?

To catch it in the act, get a cheap gopro and mount it so it can see the tach and ideally both gas and brake pedals (suction cup on the driver's side window might work). Once every 6-7 months or so might not be worth it... but it's an option.

File a complaint on NHTSA for unintended acceleration.

 

[JerryB52]

Thanks. They told me at Hyundai that I can try carb cleaner in the throttle body while running. They said they sometimes get gunked-up....

 

[QuantumRift]

The throttle is computer-controlled. So I would first thoroughly examine the area around the base of the gas pedal where the switch is that send your 'foot to the floor' command to the computer. After one nasty winter a few years ago, I discovered a lot of sand, small pebbles and rocks, and other bits of debris and so forth had packed in and around that little switch. I know this sounds simplistic BUT debris in that switch CAN interfere with the signal the computer gets. Clean that area thoroughly and I mean thoroughly.

Quant

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[QuantumRift]

Need to try all the simple approaches first and get the thing looked at before filing a complaint like that.

Q

Almost sounds like the cruise control not disengaging, trying to maintain speed while you're slowing down. Check to make sure your brake lights light up when you hit the brake pedal (check for faulty brake switch). What year/trim is your car? Smart Cruise enabled?

To catch it in the act, get a cheap gopro and mount it so it can see the tach and ideally both gas and brake pedals (suction cup on the driver's side window might work). Once every 6-7 months or so might not be worth it... but it's an option.

File a complaint on NHTSA for unintended acceleration.

 

[JerryB52]

Thank you for the replies. I will clean the throttle body thoroughly with carb cleaner. This has only happened 4 or 5 times in almost a year. $300 for new throttle body so I will try all other remedies first.

 

[QuantumRift]

I have a background in aeronautical engineering. I'm a network engineer now. Over the years, I have consistently observed (over and over) that 90% of the time, the SIMPLE solutions ARE the BEST solutions to fix a particular issue.

Thank you for the replies. I will clean the throttle body thoroughly with carb cleaner. This has only happened 4 or 5 times in almost a year. $300 for new throttle body so I will try all other remedies first.