I have a 2002 Xtreme Blazer that has developed some problems. Since I first got the Xtreme a year ago, the engine had a bit of a rough idle. The CEL came on 2 days after I got it. I called the guy I got it from and he had just had the bank 1 oxygen sensor changed. I found a vacuum line off, replaced it, and most of the rough idle went away. As well as my problem with the heat/AC switching places where it vents at. I recently have noticed that I had a slight loss in power that started a few weeks ago. Then the CEL came on. I checked the code and it was P0101. I pulled and cleaned the MAF and checked the air filter. In the process I found the large goose neck hose from the engine to the breather cap was off. I put it all back together and it got a tiny bit better but nothing major. I then changed the MAF and still didn't get any improvement. Last night I was on my way to work, and was about 5 miles from home and my engine almost died and the CEL came on. The engine had very little power. I was able to turn around and head home though very slowly. The engine was spark knocking terribly, would occasionally spit back through the throttle body and almost quit. I would put it in neutral and rev the engine just to keep it running. I stopped on the side of the road and put the old MAF back on. Nothing improved. I ended up calling AAA to get a tow for the last 1 1/2 miles. It wouldn't get me up the hill on the road I live on. I tried to start the engine after the rollback dropped it off and it would not stay running. It would try to start but would cut right off. After sitting during the night, it started right up this morning. I scanned the OBD codes and came up with a P0101, P0301, P0420. I cleared the codes then drove it back and forth on my road, avoiding the hill. When I get into the throttle, I have noticed there is a moaning sound coming through the filter box. Never had that before I started having these problems a few weeks ago. I have been told, by a friend who has owned Blazers and S-10's, that it sounded like the ignition module going bad to him. I have also noticed a rattle in my exhaust system. From my experience, I think it is the insulator cover over the catalytic converter. Had this exact same noise on my Lumina and my Dakota. Got some ceramic wool to pack between the insulator and the cat. The noise went away on both of them. Haven't done it on the Xtreme yet. Although I don't think it is a problem with the can. But I could be wrong. Anyone out there that can help me with this problem? This is my tow vehicle for my camper. The wife and I were planning a camping trip this weekend, but I guess that's off. Thanks in advance folks.

 

Well you mentioned the bad running and lack of power, and my mind started leaning towards a clogged cat converter, as that was my experience when it clogged on my 04 Blazer. Then you mentioned the rattle in the exhaust, that REALLY sounds like a bad converter, like the honeycomb inside has broken loose and wedged itself in the exhaust and is badly restricting the flow...

I ended up just gutting mine (no emissions test here in Florida) and it cost me nothing but a new flange gasket, a short piece of pipe, a couple clamps to put the front section back together since I just cut the front pipe off with a saw (which I later had welded back together when I had a muffler installed), and about an hour of time. Solved my issue completely, after 170k mine was nearly completely stopped up...

Factoring in the P0420 code (Catalyst System Efficiency Below Threshold) also makes me lean towards the cat being at fault...

My $0.02

 

You know, I was thinking about that a few minutes ago. My Dakota, which has 275,000 miles, had the same problem a few years back. Found out by taking a hammer at tapping on it. I could hear stuff rattling around inside. The guts had broken apart and blocked the exit to the cat. In NC, we do have emissions testing but I just got my Xtreme inspected, LUCKILY! The CEL came on 2 days after I got it inspected. I just replaced the ICM and it didn't make any difference. I think I will drop the cat and, at least, check it. If it has broken down inside, I will gut it. Wish me luck and thanks for your input.

 

Well, I tried to take the cat down but was unsuccessful in breaking one of the flange bolts loose. On a whim, i thought I would remove the O2 sensor and run a scope in the hole. Never thought it would come out but it did. I have a tiny endoscope that I ran inside to get a look. The exit end of the cat looks perfect. Nothing broken loose and everything looks to be a very light grey or white color. Nothing on that end looks clogged either. I would take it to a shop and have the cat replaced but I would never be able to drive it there. Not enough power.

 

The cat on these actually has two separate honeycomb sections inside the single converter, I'm assuming they did this not have to do the pre-converter/converter combo that some vehicles use. It's very possible the forward one broke loose and has clogged the honeycomb in the second converter, but you'd never be able to see that from the downstream O2 sensor side...

Tapping with a hammer is a good way to test for a busted up converter though, it'll make an obvious rattle or sound like there's rocks rattling around in there

 

Gonna look into it again this morning. Hopefully the PB Blaster will help me break that other nut loose. Be back later with results.

 

Ok, the PB Blaster did the trick on the other nut. Took a saws all and cut the cat loose earlier. To my amazement, the honeycomb was completely in tact. It had broken loose from the outer housing though. There was a lot of loose stuff laying inside the inlet of the cat. I shook out a good shot glass full of "stuff". I figure this could have clogged it up. Since I already had it off, I gutted it. Got a coupler pipe and a new gasket and put it back on. Anti-seize on everything. Cranked it up and let it run till I went in and cleaned up our bathroom after a total renovation. Probably ran 30 minutes or so. Hopped in the blazer and took off. This car has never had that kind of power. Going to take it out of the neighborhood tomorrow. Just a bit scared since the episode Thursday night. Don't like calling AAA if I don't have to. Thanks for all your help. By the way, right now, I have no codes on my OBD reader.

 

Awesome! Yeah it was a night and day difference after I gutted my clogged converter... I think it's when people gut a old clogged converter and free up power that gives others the misconception that gutting ANY converter unleashes power. Fact is, a perfectly working converter hardly restricts any flow, so a good working converter isn't robbing any power.

Glad to hear it helped and I hope it has solved your issues, I'll be looking forward to an update!

 

Well, I took the blazer on a road trip this morning. About a 40 mile round trip. Ran like a new car. Thanks for your help.