Like some others mentioned, my '03 sometimes comes out of park or idle with a loud fan noise(not reving engine noise) or a vaccuum sound and struggles to find much power. It usually works itself out after 5-15 seconds, but it is strange. An online GM mechanic suggests it may be a failing Fan Clutch. I am going to take it to my mechanic later this week and hope to have it resolved. I will keep you posted on what he finds. In the meantime i am going to drop in a K&N cold air kit.

thanks

 

I'm pretty sure that's just part of starting up. My 03' does pretty much the same thing as far as I can tell.

It concerned me too, but I'm thinking now that it's just the engine starting.

 

Ranger,
I thought so too, but yesterday it happend after I picked up my daughters from a movie. So the truck had been running for some time, and the sound kicked in as soon as i shifted out of park/idle, and lasted for about a minute so it seemed.

 

This happens with my 02 Blazer. If its cold, coming from a stop, it's almost like it gets stuck in first gear until I reach a certain RPM and then its fine.

 

Yep, it doesn't sound like the engine over revving, but definately overworking. I even try to drop
it into 3 to get it to run normal. I am looking into whether it happens more when low on fuel.

 

Sounds like the normal operation of the fan clutch to me. My 2000 blazer does it, as did my '94 S-10. Usually doesn't last more than a few seconds though. If it is lasting longer, perhaps the fan clutch isn't functioning properly.

 

I have always had the same problem (big fan-like noise complimented by a large loss of power). It only used to occur every once in a while after startup and it would work its way out in 5-15 seconds through higher revs. But now not only does it occur almost every startup, almost every time I come to a complete stop it happens all over again, we need to figure out this problem.

 

my 03 is doing this also, not all the time though, i thought it was just when the engine was cold at first but its happened to me whens it warmed up too
however i have noticed that if you let your truck idle for like a minute before actually shifting to drive it doesnt really happen.
not sure if this is normal, but seems to be a common thing

 

mine gets stuck in first at WOT from 3500 to 6500 making a sh*t ton of noise but not making any power annoys the hell out of me but oh well im dealin with it for now waiting to see if the new fuel pump fixes the problem.