What are your fuel trims at idle and cruise? Is the IAC original or aftermarket? This type of behavior is pretty common with the aftermarket ones.
Very normal fuel pressure. Check fuel trims. I had '04 leaking around the EGR gasket but not enough to set a code. ~=15-20% at warm idle. Made for high idle and less than happy when cold.Hello,
I have 2004 Ford Taurus with high idle issue. I did a live data scan with my OBD2 tool and the RPMs during cold start is approx. 1450 and when driving or at operating temp, it stays around 925. Also, when the AC/heat is on, the RPM drops to around 750 to 800.
There are no check engine light/codes. I sprayed brake cleaner around all the hoses/vacuum lines and it didn't make any difference. I swapped the throttle body & MAF sensors and it didn't resolve the issue. Also, the fuel pressure fluctuates between 39.5 to 41.5, so could it be a bad fuel pressure sensor, faulty fuel injector(s) or the manifold runner control o-ring?
Thanks in advance.
It leaks or not, best check fuel trims at warm idle and let it tell you if you have an issue. Pic of mine after fix.Thanks. I will check the EGR gasket area and the o-ring going into the intake.
The idle drops when the IAC is unplugged, but didn't check the RPM.With the engine running at temp, unplug the IAC and the idle should drop to a just barely running 450-500 rpm. If not, someone may have opened the bleed air adjustment or throttle stop to raise the idle, and your cleaning everything may have fixed the original issue..
Another possibility is a sticking evap purge valve, it can be cleaned in the same manner as the IAC
The IAC was replaced and the new one is OEM (Motorcraft). It has 76k original miles.All the data looks pretty good. Is the IAC original? Miles?
Just for discussion. Engine rpm/power is managed by air flow. Throttle manages air flow, and IAC manages air flow, and PCV manages air flow. Then leaks add air.Okay, thanks.
Only MC PCV is acceptable. Aftermarket is not like OE.Thanks. So, if I have it on Drive, it would easily drive up to 20 miles on level ground and I don't need to put my foot on the pedal.
I didn't see any leaks by the PCV elbow or line, but will clean or swap the PCV if required.