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.
2004 Taurus High Idle issue
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.
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.
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I haven't checked the fuel trim levels. The IAC, MAF and throttle body sensors are OEM.
Try cleaning out the IAC with some throttle body cleaner, it may have some carbon preventing it from returning to its default stop. Same with the throttle blade, take the intake off and clean both.
Forgot to mention earlier, the valve cover gaskets and intake manifold gaskets were also replaced due to oil leaks. When it was replaced, the IAC, throttle body, IRMC were all cleaned but didn't make any difference in the idle.
Wondering if I should replace the fuel filter and fuel pressure sensor or do a smoke test for any hidden vacuum leak.
Wondering if I should replace the fuel filter and fuel pressure sensor or do a smoke test for any hidden vacuum leak.
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.
Wrong gasket on the EGR to intake. Small leak.
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Thanks. I will check the EGR gasket area and the o-ring going into the intake.
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.
Any thing +/-10% not an issue. Best not trying to fix things not broken. I had bad data, traced it to this, first time in all my 11 Bulls had this. Lots of things can cause vacuum leaks, but first test to see if you have an leak. If not move on, it it is leaking, then find out where.
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Yes, will do a scan and share the results.
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
Another possibility is a sticking evap purge valve, it can be cleaned in the same manner as the IAC
All the data looks pretty good. Is the IAC original? Miles?
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
Where is the bleed air adjustment or throttle stop? Also, I will try cleaning the evap purge valve.
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?
Thanks.
Another thing I noticed, when I let go off the gas pedal, it takes about 2 to 3 seconds for RPM to drop. Could this be related or something else going on?
purge sounds more likely. It wouldn't throw a code if it completely closes within a few minutes after the engine shuts off (when the evap monitors run)
Okay, thanks.
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.
The PCM adds fuel to math that air as measured by the MAF. If idle is too high and trims are in line, then one of the managed air flows is high. The PCM is making it high.
I know from experience, it you open up the throttle plate screw idle stop, it will not make the idle go up. PCM just adjusts for that. Things that make the PCM add more idle. PS pressure switch, and A/C clutch relay. Both to correct added load. If the A/C clutch it called for and it does not engage or no load is experienced when it does, idle jumps up and is not matched by load.
From experience: PCV stuck closed/ or wrong size for the car and idle will be low or high and the PCM will not try to correct. Had cheap Autozone PCV and car would drive 30 mph on level ground.
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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.
I didn't see any leaks by the PCV elbow or line, but will clean or swap the PCV if required.
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.
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