Old Lawnmower Gas

Hi All,

First-time poster. Love the forum.

Okay, I did something stupid, and it's all resolved, and I've already beaten myself up (and my wallet) so there's no need to "tsk tsk" me! I thought it might be helpful to share the results of my expensive "experiment."

I put old lawnmower gas in my 2007 Prius. It was at least a few years old. I first poured it into a light-colored tub to see how it looked. It separated a little bit, but otherwise seemed clean enough. I searched a bit and found that if there was enough gas in the tank, a little old gas was fine (in general, not Prius-specific.) As it turned out, I added about a gallon (maybe more) to a half tank of gas. Why? The alternative was to bring it to a haz waste collection day, and I thought it would be fine when mixed with more gas in my tank.

A few hours later, we went for a drive to the park; my wife was driving. There was some hesitation almost immediately, some jerkiness on pressing the accelerator. I told my wife to give it more gas, hoping to "push through" the bad gas. The car kept running, and got us to the park, where I took over. I re-started the car to go fill up the tank. A few of the yellow warning lights came on. I filled it with premium, trying to be nice to the engine, but on my way back to the park, I noticed it was running on battery alone, and that there were only two bars left. Back at the park, I restarted a few times, again trying to burn through the bad gas. Each time, it would start the gas engine, and I could see that it was charging the battery when it did so, but then it would stop. After 4-5 tries, it refused to try any more. It was frustrating at that point not to have a key to turn, to force a starter to turn, like on a more traditional car. At this point the car would shift into park or neutral, but not drive or reverse.

So I called AAA. The tow truck guy said, "Oh, just add dry gas." Yeah, well, I explained, the engine won't even turn over. He tried starting it with a battery booster attached to the fuse-box terminal, but that really wasn't the problem, it seemed to me. So he towed it to Watertown Toyota. 10 miles, first 3 were free, each additional was $3, $21 total, plus $5 tip.

The dealership scolded me for putting old gas in. "These hybrids are really sensitive," etc. etc. Long story short (too late,) they changed the spark plugs, cleaned the fuel rails, and pumped as much from the (full) bladder/tank as they could. They filled it with gas, plus "fuel additive," then with my permission a hybrid tech drove it 60 miles home that night, and in again the next morning. They said it was doing fine, but they can't be sure they got all the bad gas out of the bladder, so call them if any engine lights came on. The car has been fine for the last few days since then. Here's what I paid:

- 4 hours labor $384.00
- 4 spark plugs 54.72
- full tank of gas 39.71
- shop supplies &
haz waste remv 3.00
- sales tax 2.74
TOTAL $484.17

I specifically asked for the engine codes for the good of society and to expand global scientific knowledge. Here's what they gave me:
"Codes for multiple cylinder misfire (P0301, P0302, P0303, P0304.)"
I see that this matches a list that someone posted here:
http://prius.ecrostech.com/GenInfo/DTCs/EngineECU.htm

Anyway, just wanted to share my experience. If anyone else wants to try, I have a gallon or two of old gas left.

Tom.