I have a 2009 Genesis 4.6L with 127k miles on it. 2.5 years ago when being driving, it stalled as I was approaching a red light at a speed of around 10 mph and applying the brake. I came to a stop, shifted into neutral and restarted it. It revved up to the max at 8000 RPM instantly. I shut it down right away and waited 30 seconds before restarting it. This time it started up normally and drove fine. My thinking is that the car stalled because of a safety mechanism that cuts out fuel/air to the engine when an abnormal condition is detected.
I did not experience this issue again until now. A couple of days ago when I started it at home, it revved up to 8000 RPM instantly. I shut it down right away, waited one minute and started it again. It started normally and has been driving w/o any issue.
Can a failing throttle position sensor or crankshaft position sensor or some other sensor cause this?
I agree with @Mustangman . . . hook up a code reader and/or scanner and tell us if you retrieve any current and/or stored fault codes that may be related to your concern(s)
Maybe you just need a good old throttle body cleaning?
Thanks for your responses. Sorry, I should have mentioned that check engine light didn’t come on either time and no fault code was logged. I wish a code was logged :). Car is just as it was before redlining, as though nothing happened at all.
Transient problems can be a real pain to capture. The last 2 I had to find - a failing transmission sensor in a Ford and a failing high pressure fuel pump in an Audi took me quite a bit of time to find.
I used an Autel app on my android tablet with an Autel bluetooth OBD2 adaptor to connect to live data. I then tried to capture data from the suspected sensors. On the transmission I looked for drop-outs from the speed sensor. On the Audi I looked for dropped high pressure fuel readings. It took quite a few tries to verify the root cause in each case.
I would suggest taking data on the throttle pedal sensors to see if they match and if they spike. I would take readings on the throttle sensor to see what it looks like when the RPM shoots up.
Thank you for the detailed response Mustangman. To find an intermittent problem one needs to have the OBD2 adaptor plugged in while driving around. Is it okay to do that?
I have used OBD2 many times to read the stored codes and fixed things many times. I am not sure how to take the readings on the throttle pedal sensors and throttle sensor. Will OBD2 capture those or do I use a volt or ohm meter?
Yes, but helps to have a buddy drive while you take data. OBD2 streams that data live. But you need to have a tool to both read and capture a snapshot of that data. That is why I specifically named the Autel. Walmart and Amazon and others sell them. Search for Autel AP2500E.
I agree. Besides the throttle position sensor check the IAC (Idle air control) if your car has that. My Harley had an idle problem, it would either idle too low and stall or idle way too high. The IAC needs to be cleaned once in a while to unstick it. I’ve replaced both TPS and IAC and my Electra Glide purrs like a kitten! Just kidding!
