All summer my truck has been whistling when real hot through 2,000 to 2,200. It sounds worse when the A/C is on but I haven't ruled out a vacum leak yet. The A/C is on when it is real hot so I'm not sure.

It is also rough and sputters at idle during these times. Could it be a vacum leak? Had the K&N. What about the MAF sensor?

Truck - 70,000 miles with FQR at 50K.

Help!

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'97 F150 Lariat, Flareside, white/sliver, SC, ORP, 5.4 (FQR 8/99) running Mobil 1
Mods: 305/70/16 GY ATS, AR Baja wheels, dual exhaust, Smittybilt Nerf Bars, Edelbrock IAS Shocks, K&N Filter, Carbon Fiber Bug Gaurd and rigged the fog lights too.

On Order: Supercrew 4x4 Lariat, Black, 5.4 and all the goodies.
Planned mods: 305/70/16 ATS, AR Atlas 16x8, Dual Exhaust, Toneau Cover, Expedition Console Mod and Smitty Bilt Tube Steps.

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Don't know if you've got your answer yet but I'm pretty sure you have a bad idle control valve. Sits just behind and to the left of the throttle body. Easy to change and is not too expensive.

 

Kirt: back when I had my 97F150 my husband changed my spark plugs and accidently knocked some little plug off the engine. (how one manages to knock something off the engine and not know it is beyond me but he did it) So I take the truck out to test drive it and check out the new plugs. I'm driving down the road when my ck engine lite come on. I pull over and thats when I notice the high pitched wind noise coming from the engine. I was able to drive it back home but couldn't find the plug that dear husband had knocked out so I swiped one from his engine. After all, he was the one that had lost mine I don't know if this is what your problem is but when I lifted the hood, if was really easy to track down where the air was coming from and then just replace the plug.

 

First of all, thanks for responding! I appreciate the ideas!

basshawg: Do you think the idle control valve is making the whistling noise or just the rough idle?

tina: Do you remember if it made the noise all the time or just at certain RPM?

Thanks in advance for your help!

 

Sounds like cracked intake or intake component. Crack opens up when it gets hot. Closes back when it cools off.

 

Yes, I would think so but can outside temperature make that much difference?

Also, why only at 2,000 - 2,200 rpm? Is there something that is triggered by this rpm?

I guess it is possible that when they shoe-horned the FQR in last fall they cracked something. Not sure now, 20K miles later, what they would say.

Thanks for the input!

[This message has been edited by kkirt1 (edited 09-22-2000).]

 

Kirk: mine whistled all the time. Louder when driving but still enough when just sitting still for me to find it when I raised the hood. Can you get someone to press the accelerator while you stand on the side (never stand in front) of the engine and try to find the noise???