01 Tahoe whistling

[tbush]

I have a 2001 Tahoe 5.3 v8. It makes a bad whistling noise at start up and when acclerating, the truck struggle to get to 50mph and won't go above 3k rpm. Also idles rough at a steady 500 rpm. i'm ceartin its not an intake leak as i've sprayed all around with ether. Belts are good. Any help? Thanks

 

[Rigwhore]

I can't help but think vacuum leak

 

[Mechanic421]

Clogged cat.

 

[Mechanic421]

But must test.

 

[Contend997]

Sounds like a vacume leak but if you have a cloged cat or muffler plugged due to cats that would do the same thing

 

[Rocket Man]

I also suspect clogged cat(s). Have them checked for restriction.

 

[rockola1971]

Did Eddie Murphy stick a potato in YOUR tailpipe?

 

[afpj]

It was a banana

 

[tbush]

Sounds like a vacume leak but if you have a cloged cat or muffler plugged due to cats that would do the same thing

wouldnt a vacum leak show up when spraying ether? also how would i find out if its a clogged cat. these trucks have 2 right?

 

[Rocket Man]

I had a mechanic test mine, not sure how it's done but they said my left was 85% restricted and my right was 50%. And yes we have 2. Mine had pretty much the same symptoms as yours except the whistling. Another clue is if it clears up a bit when it's cold but gets bad again as soon as it warms up and plugs again.

 

[rockola1971]

wouldnt a vacum leak show up when spraying ether? also how would i find out if its a clogged cat. these trucks have 2 right?

Usually they just hit it with an Infrared thermometer at the inlet, middle and outlet. The temps should be near one another. A bad one will be substanially cooler on the tail side vs the inlet (toward engine). Harbor freight has the IR thermometers cheap. Usually (bot not always) the downstream oxygen sensors catch a bad cat. Thats the whole purpose of the downstream oxygen sensors. The code is for the downstream(s) being out of range or something along those lines. They have nothing to do with providing information to the PCM for fuel injection adjustments, thats the job of the upstreams (forward of the cats).