Was told to check out my exhaust/cat to see if maybe that was my problem.
How hard is it to remove and take a look?
How long would it take a rookie, and should i do it?
I got some serious crackle going on after a short drive, and i used to smell what hinted too rotten eggs in the cab about a year ago, but not anymore.
The crackle is the Cat getting hot, and it gets hot when engine is running too rich.
Pull out at least 2 spark plugs and look at the tips, very light brown means good burns, blackish is Rich burn.
How old are the O2 sensors?
They are good for about 100k miles, after that they can start to make engine run richer and richer as they get older, so new ones will pay for themselves over the next 100k miles in MPG.
Only the 2 Upstream O2 sensors need to be replaced, the Downstream O2 sees cleaner exhaust, after the Cat, so usually lasts twice as long, but up to you.
To check exhaust flow it is best to use a vacuum gauge($25)
Read here for what and how to test:
http://www.gregsengine.com/using-a-vacuum-gauge.html
Gasoline engines are still air pumps, engineers can add fuel injection, run with no distributors, and add a sh!t load of sensors and controls, but engines are still just air pumps, so vacuum gauge can tell you ALOT about engine condition, and if it is pumping air IN and OUT(exhaust) efficiently.
Clogged exhaust will cause slow acceleration and limited power at higher speed/RPMs, idle would be fine.
You can also bang on the pipes, Cat and muffler with rubber mallet or if cold your hand and listen for rattling, rattles are broken off pieces inside the exhaust system.............a bad thing.
When you burn gasoline(
Hydrocarbons) with
Oxygen, one of the by-produces is
H2O(water), so exhaust systems rust from the inside out, and also why you often see water dripping from tailpipes.