Just cleaned my throttle body with CRC TB cleaner as per 60k maintenance. I have 101k. Zero problems or noises before hand, immediately after cleaning I can hear this vvrrrttt sort noise coming from the top of the engine. Truck still drives and idles great. Any suggestions it's a '96 4.0. The wooshing is the fan spinning and no check engine lights.

 

Idle air control valve, it might be sticking.
Remove it, clean it, put it back. Do NOT move the plunger in away way shape or form.

 

Thank you, I'm unfamiliar with the idle control valve. I'll search.

 

Looking at the throttle body from the front, it is the 2nd thing in, unplug it, unscrew it, remove it, watch the gasket, dont break it or loose it.
Using carb cleaner and your ex-wifes tooth brush clean the plunger, also clean the port it seats into.
Once done put it all back, plug it back in, start the engine.
It will be hard to start because of all the carb cleaner in the throttle.
The IACV is a electric motor that controls idle speed by moving the plunger in or out to let in the correct amount of air.

 

Interesting I wonder if that is the intermittent hard start issue Iv been having. Very randomly I have to crank it twice to catch hot or cold. Thank you for the help BTW.

 

Quick update, upon removal the gasket must be missing and it would seem that the plunger portion broke off as it did not come out in one piece. I will order a new one with gasket and pull the old one out with needle nose pliers. Scanning other threads I noticed that there is a cheaper sensor available. Has anyone confirmed this?

 

Yes, AC151 from RockAuto works great and is identical to some more expensive replacements.

 

Sweet, ebay has new ones for around $20.

 

Update: I tested the old stepper by removing it but keeping it plugged in with the engine off. Then turning the key to position 2. The tip retracted a bit, I removed the key, the tip flew off the stepper motor. Then tested the new stepper motor with the same results. I am beginning the think my issue is actually the alternator bearings.

 

Sometimes you can isolate a mechanical sound by listening through a stick (broom handle from SWMBO approved unit, usually not her favorite flyer) or long screwdriver touched to each item being turned by the belt. Sound travels faster throuigh a solid, and you can hear above the fan noise. You can also remove the belt, if noise goes away you know it is a rotating device, then you can spin each one feeeling for roughness.