Reader Question: Hello,
I need help on my 2001 Nissan Altima 4-cylinder GXE 45K mi idling problem.
During startup, I am getting high RPM about 1200-1300 RPM even after warm-up. When I rev it goes down to 800 RPM, the RPM or rev start to hunting (up and down between 900 to 700 RPM). It does not stay to 800-RPM steady (normal). So far, I change spark plug, wires. There is no engine code.
Any suggestion is greatly appreciated.
I would inspect two items first. Look and listen for a vacuum leak under the hood somewhere. Start the engine, listen for a hissing noise, and inspect the rubber vacuum hoses and their connections to make sure they are in good shape and there are no leaks.
Double-check the air cleaner installation and the air cleaner box for a good sealed fit. Run your hands under the plastic ductwork from the air cleaner to the engine checking for leaks.
Second, I would ask your mechanic to clean your throttle body of any carbon build up that might have accumulated there. This is a pretty inexpensive and quick maintenance item that can usually be done while you wait.
Most fast lube oil change places are capable of doing this for you as well. A dirty throttle body can cause slow starts and erratic idle speed.