more strange behavior

Drove my green car on its first highway trip. Houston to Austin, about 200m. Going there, it's flat highway for about 150m, then kinda hilly, and more hilly the last 10m or so. I cleared my MPG meter starting off and got 53mpg consistently on cruise at 58mph until I hit the hills. At arrival, I averaged 50.1mpg on the trip and felt pretty good.

A cold front hit while I was in Austin. Lotsa rain. When I started the car to head home, it sputtered and missed for about a minute, but never died. I started driving and a strong smell of fuel filled the cab. I opened the windows and it never came back.

Thunderstorms all the way home, so I was driving slower, probably averaged 50mph. However, my MPG dropped. By the time I got home, the overall trip averaged 45mpg. I would have thought it would increase with the slow driving.

I don't see any signs of fuel leaking under the hood, and it hasn't sputtered when starting again. BTW, it did that sputter thing once earlier, but all the rest of the times it starts. Always seems to run fine with plenty of acceleration available.

I've run into different MPG readings before, starts out high and over the course of driving on the interstate all day, it gradually decreases. I understand initial reading will be off, but after 100m or so, I would think it would level off. This was a much bigger difference though. Wondering if I have a fuel leak somewhere, maybe an injector o-ring (I struggled to get those to seal when I was first getting the car back together). But, don't see any leakage.

 

I'm wondering if it's that exhaust flap on the cat. This car hadn't been driven in 5+ years until I started working on it over the summer. Still, I'd only ever started it for a few minutes until last month. Since then, I've tooled around town on city streets, and a couple of short jumps on the freeway, but always nice, warmer weather. Saturday was the first time I turned the heater on as well, which now that I think about it, is the same time I smelled fuel, but that's could be simple coincidence.

And, obviously, it was nowhere near freezing Saturday, but temps did drop 20-30 degrees while it sat all day, and colder than it's ever run. That might have been the sputtering, that flap stuck shut, or closing shut, or opening, IDK, and messing with the fuel mix.

Next step: I delete my OEM cats anyway - figuring they'll get stolen sooner or later, might as well be me - so I'm going to replace that whole assembly and see if my sputtering goes away. Use the $700 to go gamble at Lake Charles - no different than driving these cars, right?

 

Ok, it was the obvious problem - one or more of my injectors blew an o-ring. Today it sputtered at start up again and I immediately opened the hood and saw the wetness.