
So my Hyundai Santa Fe 2011 is having issues accelerating during the 10-20mph. Once it's over 40mph it's easier for it to get faster. If I press the pedal when it's barely moving, it makes a noise so I've been pressing it slowly to get up to speed. Does this have to do with the throttle position sensor or the catalytic converter is bad?
Also with my Pontiac G6 2006, it is having issues accelerating.
Thanks for any input!
Comments

I would say that if the check engine light is not on yet, you most likly have an issue with your automatic transmission. What you need to do is either get a professional scanner or if you don't have DIY skills, take the car to Hyundai dealer and let them do a full system scan.
They should get one or more codes. Those codes can help you undersand what is going on. This problem can be caused by many things, and you don't want to start throwing money at your car. I would say that proper diagnostics is neccessary here.
Let us know what you find out.