As of yesterday I wrapped up the project on my truck that I hope will cure the engine whistle/whine issue. To sum it up:

Replaced 4 gaskets:
-Lower intake gasket*
-Upper intake gasket
-EVR (EGR?) gasket
-gasket for the Air filter feed to intake

* = Primary replacement objective

After a quick fresh oil change & driving it for the first time in 3 weeks last night, I observed NO further whistle sound (At idle or deceleration like before). Engine was really quiet at stop signs. I need a little more time driving it before I can say for certain the gasket replacement fixed my engine whistle/whine sound, but early indications would seem to suggest that the lower intake gasket was the culprit in my case.

Replaced distributor, rotor and cap:
-Side job here, (Originally I was after replacing just the rotor and cap) the distributor cap screws rusted hard to the old housing (And broke). EZ outs helped but not enough to save the old distributor. Currently working to correct my trucks new timing issues (Now it stalls a lot when I put it into gear and idles rough). Still working on this but will post again with final engine noise results, parts used/replaced, etc. after a good several days of driving.

Hopefully this one can be put to bed.

Thanks,

-91HT

 

It's been a week of solid driving in my 91 F150, and since completing reassembly of the intake system with all new gaskets and a new distributor, I have heard NO further engine whistle.

I've driven it hot for long periods and to me it sounds like a whole new truck. It's temperment has improved as well as a result of the recent work:

-Transmission now very rarely jumps when accelerating from a stop or from faster acceleration from a stop.
-No more loud whistle in engine
-standard shifting feels smoother
-Engine idle noise virtually silent now at stops

So that does it! I hope this helps in case any others have this issue (Of course results and circumstances may vary). It's a real pain in the *&% to get at the lower intake gasket, but it's more time consuming then anything. I learned a lot on my first Do-It-Yourself truck surgery.

Info:

AutoZone Part #:
Part Number: MS95647 (FelPro Intake Manifold Gasket Set *Upper and Lower) Cost $8.99

Other Gaskets replaced:

AutoZone Part #:
Part Number: 72649 (FelPro EGR Valve Gasket) Cost $1.99

AutoZone Part #:
Part Number: 81158 (Permatex Silicone Sealant - Black) Cost $ 5.99

I replaced one other gasket between the air filter and upper intake (Located next to the throttle body assembly) but forget what it's called.

Thanks for all the help, suggestions and info! I think we may be back in business.
Any questions, please ask.

91HT

 

Reviving this thread to find out if this was the sound that the OP was experiencing, this sound has annoyed me long enough!

 

Idler or tension pulley. Pretty cheap and easy to replace and eliminate as a possible cause.

 

I bet he's glad you solved it for him after 5 years!

 

Maybe other people have the same issue and found this thread like I did?

 

Maybe... If so, they're apparently solving those issues with the info that has been in the thread for the past 8 years, because they're not asking questions here.

 

You da man Steve