So recently I started to hear a whistling noise coming from unknown location when I was reaching 30MPH or higher, along with a noise of metal on metal on my 04 LJ.
So yesterday as im driving down the highway, going 60mph, my jeep all of a sudden hiccups and starts flashing the CEL. Then I lost about 70% of my power on the freeway, the max i can go was 40mph. No matter how much I pressed the pedal it would not speed up. It would rev the engine higher RPM but would not speed up. Like someone took my I6 out while driving and stuffed a 2 cylinder in it. I head home and cruise 20mph up my street(speed limit is 40) with CEL light blinking. Also when I would rev the engine and try to go faster, I would hear a whistle like sound, kind of like a vacuum.
I pulled the codes and I get:
P0300 - Missfire
P0305 - Cylinder 5 Missfire
p0306 - Cylinder 6 Missfire
p0456 - EVAP leak
p0432 - Bank 2 Downstream 02 Sensor
Quite a lot of codes. So I went to my local part store and purchased a Bosch 02 downstream sensor for my p0432 code. Replaced 02 and all the codes went away. I took the jeep for a test drive and guess what. Still the engine was severly low on power. Next I figured it was the coil pack specificly over cylinder 5 and 6. Since those were the cylinders throwing missfire codes and that one coil pack controls two cylinders. Got a new coil pack and same thing, low power. Finally I decided it was the catalytic converters.
I assumed it was catas because the missfires were not really missfires. There was no engine shake and the engine ran fine at idle.
So after much struggle and stripped bolts, me and my dad got the catalytic converters off. I was shocked at what I saw inside:
As you can see, the actual converter webbing things is suppose to look like picture 2. In picture 3 the webbing broke down and fell apart and clogged the hole. That part of the cat was connected to cylinders 4-6. So this was the main reason the computer was calling missfires. I tried the "bang on your cats and see if you hear any loose metal" but that didnt work for me.
Anyone reading this in the future, if you have these symptoms then its most likely your cats. At first I was hessitant to believe it was the cats because my jeep is 58k Miles and only a 04. No reason for the cats to go bad. Well I was wrong. Too bad I was just 1 year shy for my 8 year warrenty on the cats.