My 2004 Ford FreeStar 3.9 engine, 149000 miles throws code P0507, Its idle speed very high, around 2000 rpm, and no change when drive in low speed. I did two tests,
1. Pull out idle air control valve electrical connector, the engine shut off immediately.
2. Pull out Throttle Body electrical connector, the engine speed did not change
Then I replace the two parts,
1. Bought a brand new idle air control valve from Autozon, and replaced it. same problem.
2. Bought a used throttle body, and replaced it, did not fix the problem.
Based on my pull electrical connection test, the Throttle body has problem, but my replacement did not fix it. Can someone give me some advice for how to check and fix it?