2006 Kia Optima - low power on hills, passing

Maintenance/Repairs
,
21

Haven’t needed the heat until just recently, so just noticed it. However, the temperature gauge on the dash hasn’t been showing any signs of trouble. It’s been steady and constant, and perfectly normal.

I asked about the compression yesterday. He said that was fine. Checked while he was replacing the plugs.

It sounds like, then, that you’re suggesting another possible angle to this–a stuck thermostat, which has in turn clogged the catalytic converter.

The bottom line I see here is, when I research the symptoms online, I find the closest possible cause being a clogged catalytic converter. Okay, you say it might not throw codes for that even if it was so… but then, I’ve had bad cc’s on other cars, and my understanding is that they glow red hot, etc., when they’re clogged. Mine clearly isn’t it. I was under there yesterday looking at it.

22

I just remembered something that happened this summer which I’m sure is relevant to all this. A few times (it was very sporadic) the car would suddenly lose almost all power, often at a stop, occasionally in just low-speed city driving. It only happened for a second or two, then there would be a POP sound that seemed to be coming from directly underneath the car, like a muffled backfire–and then the car’s power would immediately come back, more or less as normal. As I say, this happened a few times over the summer, maybe earlier… but never often enough where it was causing a constant, consistent problem. As I recall, it seemed to happen mostly when the car was cold. I’d made a mental note to look into it at the time, but then it seemed to go away for a while, and it must have slipped my mind. I only just remembered it.