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99 F150. 4.6 2v. idle air control valve and its housing has carbon built up. Any suggestions on what oil to use or if this is not a function of oil choice? Thanks in advance.
Best oil choice for clean idle air control valve?
- Thread starter thickvthin
- Start date
Look at your air filter. What is your driving style, stop and go, long idling?
It falls under periodic maintenance (cleaning) for the IAC along with MAF (Mass Air Flow) sensor.
I don’t think the OP is using the oil to clean this - I think his question is based on what oil would minimize the carbon buildup from all the PCV blow by in the intake that is causing the carbon buildup on the idle air control valve.
Being a '99 it begs the question of when was the last time the PCV, and related hoses, were cleaned/replaced.
@thickvthin are you having any idle problems? Just curious. I am replacing the IAC on a 98 Accord 4 banger due to lean surge.
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The truck has 225,000 miles. Since beginning of covid it has not been driven much. I have an elderly that i take care of and she prefers the low height of her rig as opposed to the truck. @Brian123 asked some good questions!!! I checked the air filter and it was filthy. And to keep the battery charged I idle the truck for 20 minutes every 2 weeks. I love the truck and plan on keeping it for ever. somehow i slacked off on maintenance and whatnot but am getting back into it. I noticed the truck had a hot start issue, i.e., starts great with cold engine and runs great after that, but if you shut it off and then try to start, it will cause crank times of 7 seconds or so and do a non-normal start but run great after that. No engine codes. Fuel trims were within 3%. Have not checked the PCV. I checked the AIC first and saw it had carbon built up even on the port.
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No.
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Yes that is exactly what I was asking?
CleanSump
Site Donor 2026
Maybe Valvoline Restore and Protect. If Valvoline claims it helps keep GDI intake valves clean, maybe it will have some affect if the PCV feeds into the intake upstream of the throttle body.
I think most of the crud that gets stuck in the throttle body is dust that got past the air filter.
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thats the port that has carbon build up inside
That looks more like residue from EGR than it does from PCV.
I am not certain of the intake plumbing on your Ford, but if you’re getting that kind of carbon, that may be something that can only be addressed through periodic removal and cleaning
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I unplugged the egr in closed position about 60k miles ago. Its my understanding that is effectively blocking off the egr.
Patman
Staff member
I’ve been thinking lately that it would be interesting if someone had a slightly clogged PCV valve and then ran Restore and Protect. Would it actually make any improvement in that regard? Someone here needs to test this out
Even though the EGR is in the closed position it still leaks a small amount of exhaust gas by design.
Very good question. I suppose it's possible.I’ve been thinking lately that it would be interesting if someone had a slightly clogged PCV valve and then ran Restore and Protect. Would it actually make any improvement in that regard? Someone here needs to test this out
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