Hey fellow fitfreaks:
Hopefully you can lead me in the right direction to solve this dilemma. 3 days ago, I got 35.3mpgs for the day according to my scangauge. Nothing new there - until tonight I noticed driving home, my instant mpg seemed a little low. Looking through scangauge's memory, 2 days ago I had 17.0mpgs, and today thus far is 15.3mpgs! Now I'm highly concerned.

here's the only thing that could, I think, possibly be contributing: I live near Daytona Beach, FL and have driven on the beach multiple times since I've lived here, about a year, with no problems. However last month, a bad storm came rolling in and we had to leave fast - it downpoured and the waves started to come in quick, and before I knew it, the normally compacted, drive-on sand had turned into a washout. my car, with several others got stuck badly. I'm dropped on skunk2s, which didn't help. I got bogged down and the waves washed under my car -I was stuck until the tide receded, about 2 and half hours. Other people were stuck similarly in their mini coopers and vw beetles, and another honda, a civic for similar amounts of time. My primary concern after was the wash the car inside and out thoroughly, which I did, to get rid of any salt and sand, I cleaned in the engine bay as well and removed all of it.
But now, about 4 weeks later, this random drastic drop in mileage has got me concerned. The car sank about 1-1.5in, but the motor/tranny as far as I could visually see got into the sand only a mm or 2, hardly buried in sand (The plastic under plate however did take some sand but I cleaned it out immediately.)
Anyone think there is a correlation? I regularly do all my routine maintenance, check and change oil, tranny fluid, rotate tires... no codes are popping up.
Should I reset something maybe? Is my ECU giving the wrong info to my scangauge? So far, since I drive locally, and not too much per day, maybe 10 miles tops, the gas gauge has moved about a 1/4 of the way down from when I last filled up - 3 days ago.
I'm also concerned I might have got bad gas; always hearing the stories about water in the fuel, etc...

Anyway, anyone that could lend some assistance, it would be much appreciated! And thanks for reading this kind of long post - just need to be thorough so everyone knows exactly the situation!

-Nic

 

Corrosion of electrical connectors could cause problems without throwing a code. I'd especially check the O2 sensor - it's exposed because it's on the exhaust manifold and it can directly affect gas mileage. The ECU's don't monitor everything, things can go bad without reaching the level of throwing a code, and the codes are sometimes a 'most-likely' informed guess. I'd also change out oil, oil filter and air filter. It is likely you sucked a decent amount of salt fog into the engine while trying to get it out.

 

so 60 some-odd dollars later - oil, filter, air filter, new gas to top off - and a lot of tinkering with scangauge and the problem is solved. I'm back up to big mpgs like before. My guess is that when I last filled up, I entered how much fuel I got incorrectly, and based on the wrong fill up the mpgs got effected. I knew something couldn't be right when I was get 3.2-4.0mpgs in 1st and 2nd getting up to speed.
I reset scangauge completely, and after re-entering all the settings for the fit's engine, everything works as it should. I may not have even needed the new oil (but for peace of mind I'm glad) since I had done it about 1000 miles prior to the beach incident. O2 sensor was fine, and I observed anything under the car that looked prematurely corroded and found nothing - like I had hoped, I got the salt/sand out quick enough before anything could start being affected (besides the rotors, they were orange by the time the tide receded and I got out of my predicament!)
Anyway, thanks for the support on this Rob.