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F150 Throttle freezes

I have a 2000 F150. Last year I replaced the intake manifold. While I was replacing it I put in a new PCV for no reason other then I was there and it only cost $4 to replace. During very cold winter mornings I have ice build up in the throttle body. Research told me that this would be from a faulty valve. Truth be told I broke the Elbow coming up from the intake manifold, it was glued in place. Sealed with liquid gasket. The PCV was connected right at the elbow, not sure if this caused an issue with it’s performance or not. The original extension would not fit into the new elbow. This winter I added an extension to the elbow to bring the valve closer to the front of the engine. The throttle body has not frozen yet, but it idles poorly and will stall. Any thoughts?

Research told me that this would be from a faulty valve.

Do you mean a faulty pcv valve could cause ice build up inside the throttle body?

hmmm … well, I guess its possible. The pcv system routes the crankcase vapors back into the engine, and that could add a little heat to the throttle body, melting te ice a little I suppose. On my Corolla the throttle body has a engine coolant passage, in part I presume to prevent this problem. So I’d be surprised if the F150 design to prevent TB icing was just the pcv system. I’d expaect an engine coolant component too. Is the engine warming up like it should, according to the dash coolant temp gauge display? How far up that gauge does the needle get after the engine has been running for 10 -15 minutes?

In any event, it is important the pcv system be working 100%. Otherwise you could end up blowing some major engine gaskets, like the rear crank seal, an expensive proposition. Not a problem you want. Suggest you take your truck to a qualified mechanic and ask them to fix the pcv system componentry. That will be money well spent. With some luck you may find it fixes the TB icing problem too.

Ford has issued a Technical Service Bulletin 01-21-5

It deals with the throttle body icing up from a malfunctioning PCV system.

Contact your local Ford dealer, and order the updated PCV kit, YL3Z-6A603-AA.

And that should fix the icing problem.


Which engine do you have OP? v6 4.2L? v8 4.6L? v8 5.4L?


The TSB covers all those engines.

The engine’s aren’t the problem. The PCV system design for the engines is the problem.



You mean it applies to all those engines? Not just the 5.4L built through 11.1.1?


I look this stuff up!

The TSB is for various vehicles with various engines!

I’m not guessing!


Thank you for the comments. I definitely don’t want any further repairs for this truck. I will take it in and have someone look at it. I was hoping for a simple quick fix.

Suggest to stop by a dealership and ask them to check to make sure it applies to your engine. What I found by looking it up myself – admittedly I’m not a pro mechanic, just a driveway diyer’s – but what I found was the document 01-21-5 mentioned above only applies to the 5.4 L engine manufactured during a certain timeframe. No sense installing parts that won’t fix the problem. If you have other than the 5.4 L engine, it may be the home-brew changes you made are contributing to the throttle icing problem.

Edit: BTW OP, from what I can tell this is a “customer interest” bulletin, and sometimes those are done by the dealership gratis in the interest of customer goodwill, even for older cars that would normally be out of warranty. But only of course if it applies to your specific vehicle configuration.

OP, I have an 03 4.2 v6 f150. When I replaced my PCV it was a metal unit from NAPA and was like $30 or something. It actually has lines for coolant to pass through. I was caught off guard when I yanked what I thought was an air hose off it and liquid went everywhere. I guess by that year to correct any icing issue they run hot coolant through it? I dont know.

I also dont like the sound of “this elbow broke so I glued it on and moved things around with an extension”. It needs to be exactly as it was engineered.