Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I have been diagnosing Hyundai Tucson 2009 2.0 DOHC. The issue with this car is when at idle I press the gas pedal to increase rpm to around 3000rpm, when I remove my foot on it, the rpm drops down quickly to 2000 rpm and here it stuck for 3 to 5 second then it begins to return to Idle rpm.
I suspect the Idle air controller valve. I cleaned it and nothing changed.
Does it do this while driving? Is it the same cold & warm?
It is probably not a bad coil
I would look at scan tool data for the APP & the TPS. See of the agree. Check if the desired idle & actual idle speeds agree. Look at command for the IAC. Is the TW sensor reading properly? I would think that something is out of wack & will jump out at you. Maybe you could post scan tool data of when it is acting up & when it is normal.
Have you looked inside the throttle body to see if it is gummed up and/ dirty? Is this a cable or electronic throttle body? What are your fuel trims?
There Is No Such Thing As A Stupid Question, If It's Sincere. Better To Ask And Risk Appearing Stupid Than To Continue On Your Own Ignorant Way And Make A Stupid Mistake. Author Confidential/Unknown
agreed. Looking at fuel trims is something to check into at both cold and warm engine
There Is No Such Thing As A Stupid Question, If It's Sincere. Better To Ask And Risk Appearing Stupid Than To Continue On Your Own Ignorant Way And Make A Stupid Mistake. Author Confidential/Unknown
Topic Author
