My 1996 Honda accord with 200k miles has started acting up.
After a long vacation, I came back and the engine would seriously stutter at all speeds, especially on acceleration. I assumed it was fuel delivery, so I put some fuel injection cleaner in a fresh tank and took a quick look at the air filter. Everything seemed fine. Then it stalled and refused to start in an intersection about a month ago, that was fun.
I had it towed into my mechanic who changed the oil, replaced the valve cover gasket, replaced the spark plugs and cleaned the throttle body. The massive stuttering and stalling stopped for a bit, but now it's back again in a much more mild form and only at stoplights.
The engine will hover at around 750 rpm, and every few seconds dip below for an instant and stutter. It reminds me of turning down the choke too fast on a carbureted motor.
I've switched gas stations and upped to 89. I brought it back in a couple weeks ago to have my mechanic look it over again and he couldn't find anything wrong.
Any suggestions on how to debug which part might be causing this and how I can fix it?
The cat was falling apart. Breathing in wasn't the biggest issue. Breathing out was.
When the pieces of the honeycomb rattled around underneath it would prevent exhaust and suddenly start working again. Hence erratic behavior. I guess I forgot to mention the sound of rustling leaves under my car (before fall even hit). That was my destroyed cat.
I had a few faulty O2 sensors in the past couple years which likely led to my Cat's demise.