Clogged Cat Symptoms

[grayghost]

Vehicle is a 94 S10 Blazer 4x4 4.3 CPI 86k. I have several symptoms that I have been monitoring for a few weeks that make me think that I might have a clogged catalytic converter. These are the symptoms: Sluggish acceleration, detonation at crusing speeds, engine temp on the high side, exhaust rattle during acceleration, fuel mileage declining.

Other than that the engine runs great, had full tune up including filters 5 months ago.

Replaced bad CPI a few months ago (I've been told this could contribute to Cat and O2 sensor problems).

I've had other vehicles that have had Converters go bad so I kinda have a little feel for it. I plan on changing the catalytic converter and O2 Sensor soon, but I would like some other opinions first. Haven't had a chance to try vacuum test or have some kind of back pressure test done.

Thanks, Pete

[Fractured1]

For the cost of a new converter I think I would have it tested at a gm shop, they have the proper diagnostic analizer there...even if it test out bad and you do the repair there it would save you alot of $$$..Of coarse this is if you truely lean towards the cat being bad...But the symptoms you describe does lean that way...

[OverBoardProject]

it wouldn't make the exhaust noise, but check the PVC valve too.

[Fireplug]

get it tested fast before you blow a headgasket

[SMarquez]

Originally Posted by grayghost

Vehicle is a 94 S10 Blazer 4x4 4.3 CPI 86k. I have several symptoms that I have been monitoring for a few weeks that make me think that I might have a clogged catalytic converter. These are the symptoms: Sluggish acceleration, detonation at crusing speeds, engine temp on the high side, exhaust rattle during acceleration, fuel mileage declining.

Other than that the engine runs great, had full tune up including filters 5 months ago.

Replaced bad CPI a few months ago (I've been told this could contribute to Cat and O2 sensor problems).

I've had other vehicles that have had Converters go bad so I kinda have a little feel for it. I plan on changing the catalytic converter and O2 Sensor soon, but I would like some other opinions first. Haven't had a chance to try vacuum test or have some kind of back pressure test done.

Thanks, Pete

I used aftermarket cat and muffler when my 4.3 wouldn't pass Cali emission test. Cost was $190 Most likely your cat. Why not save time and money and replace if everything else was good. Performance, economy were great and emissions were next to nothing.