Tahoe started to run weird!

[Rocket Man]

I just drove it around the neighborhood and it threw P0300 and its smelled like cats backed up. So should I try the lacquer thinner fix?

I don’t know what that is but if they’re bad then they need to be replaced. A shop can do a flow test or there are other ways to check. And if your CEL is flashing, you’ll do engine damage if you keep driving it.

 

[MassHoe04]

Once you start approaching the 150k+ mile range, the days are numbered for converters.

This was the cat on my 05 Jeep 4.0L... The chunks you see in there were ceramic material from the mini-cat up front on the collector pipe. We don't have those on the GM trucks, but look inside the main converter in my hand.

Behind the chunks from the mini-cat, most of the main ceramic honey comb was clogged. I don't think lacquer thinner or Cataclean would have helped much!

 

[gooffeyguy]

That's when you take a piece of rebar and start gutting that cat, lol

 

[Rocket Man]

That's when you take a piece of rebar and start gutting that cat, lol

Not unless you can tune out those downstream O2 sensors.

 

[gooffeyguy]

Not unless you can tune out those downstream O2 sensors.

Or plug in some MIL Eliminator (basically a resistor on the O2 plug).

 

[iamdub]

Not unless you can tune out those downstream O2 sensors.

Or plug in some MIL Eliminator (basically a resistor on the O2 plug).

Or the spark plug non-foulers. I've seen some purpose-made variants that use steel wool in them to better filter the exhaust from the sensors.

 

[hertahoe]

So I swapped coil #1 to #3. Idled a little rough and drove it to a street that I could accelerate and it threw P0303. So that means I have a bad coil! Going to store for one to see if it solves the issue.

Edit - It worked. Thanks for all the assistance.