Hello all,

So I have a 2007 LT. The thing has been a constant nightmare really, but that's a story for another day. A few days ago it randomly got 'lazy' coming down at city speeds. If I rev it in park, it's normal, once I am at highway speeds, it's normal. So I guess around 2nd or 3rd gear, it likes to hang out around 1100-1200 rpm when I'm slowing down. It does eventually bring itself down to a fairly normal idle, but only after I'm at about 3mph.

I recently had a new catalytic converter put on due to P0420, and it ran fine. I changed out the air filter a day or two after, and the one in there wasn't really dirty, but I replaced it anyway (and no I didn't use one that gets oiled). This was maybe two months ago with the filter and catalytic converter.

Any ideas what's going on or where to start looking?

 

Try the MAF sensor connection, clean the throttle body.

 

Dirty throttle body is my guess.

What caused the cat failure? Was that fixed? Or, did you just treat the symptom.

 

Yep, sounds like textbook dirty throttle body.

 

​​​​​​We aren't sure what caused the cat to fail. Had 2 shops look at it and couldn't figure it out. The guy at the exhaust shop said the area is notorious for dirty fuel. To be honest though I have no clue.

 

Unless the cause of failure is corrected you can expect it to happen again. Modern cats don't "wear out".

As oldblue pointed out, the connector to the MAF is suspect. That is the electrical connection you had to disconnect to change the air filter.

 

Oh I know they aren't supposed to wear out. But she doesn't plan on keeping the car so I want to avoid dumping money into it.

But on topic, what do you mean by the connector being suspect? I did know that's what it was, but what would that cause? The current issue, cat, or both? Plus, what am I looking for? Damaged connection/wires?

 

Loose connections

 

Checked the plug and it was nice and snug. Unplugged it to check the connectors for both sides; they both look fine.

 

Sometimes people pull on the wires and damage then.