Error code and high idle
 

I have had a slightly higher idle after recent repairs. It stays closer to 1000 and does not drop down quickly. If I would blip it slightly or after stopping at light. The idle will hang at about 1500 for 3 or 4 seconds then slowly go down to 900-1000

Here is what I did a few weeks ago. Ive only driven for 2 days though as I was out of town.
I had loss of power and slight misfire. So I changed coils, wires, plugs and air filter. After changing the car had great power. But the idle was slightly high dropped slowly. I figured that the computer was compensating for the bad parts before and would have to relearn.

This morning. I got a check engine light on my way to work.
Autozone would not loan code readers anymore so I bought cheap one (actron cp9125). Because I wanted to read the codes immediately.

I checked the codes and it said.
p0507
Mil On


I reset the code to see if it would come back on. It has not but I have high idle still.
after my drive home (25mi). Here is what the reader said.
Ther was no error code, MIL OFF 3 inc catalyst,evap,02 snsr 5 ready misfire, fuel comp, sec air, 02 htr.

Im not sure how to read this properly....

I have checked all the vacuum hoses etc I could see and did find anythat appeared loose or damaged.

Please help.

P507 = Idle air control system RPM higher than expect.

• The PCM compares the actual idle speed with the target idle speed when the engine is running. If the actual idle speed is higher than targeted by 200 rpm, the PCM determined that the idle air control system RPM is higher than expected

Possible Causes:

• Vacuum hoses improper connection
• Drive-by-wire control system malfunction
• IAT sensor malfunction
• ECT sensor malfunction
• APP sensor malfunction
• Eccentric shaft position sensor malfunction
• PCM malfunction

Since this isn't a common code we've seen here, its difficult for us to tell you where to start or what is more likely the cause.
If I was troubleshooting this on my car, I would check all vacuum hoses and clean the MAF/IAT first (start with the fast/easy items).
Then I would focus on the ESS (eccentric shaft sensor), the APP (accelerator pedal position), and the throttle valve.