2007 Impreza

Every once in a while, after our Impreza has been sitting without being started for several days (4 days to a full week) it fails to start.

It cranks over but there is no indication it will start, no puffs or partial catch, nothing.

The first time this happened it was under warranty and we had it towed to the local Subaru dealer. They claimed my wife had flooded it by stepping on the gas while trying to start it. Not true, she knows better and never does that. Since then it has happened several more times.

Interestingly, I have gotten it running on these occasions by stepping on the gas, even though I know you're not supposed to. I push the pedal down roughly halfway and the car begins to catch, runs roughly for a second or two and then finally smooths out.

This last time the car had been sitting for six days as my wife had that much time off for Thanksgiving. On Monday this week she tried starting it and it just cranked but failed to start.

I tried and was mystified as the engine actually sounded like it had lost compression, but may have simply been cranking slower than normal. I hooked up a powerful battery charger and waited a few minutes and tried again without pushing on the gas. Nothing, although the engine now was obviously cranked faster. Again, the sound of the cranking sounded different from normal.

I pushed the gas halfway down and resumed cranking and this time it caught, ran rough and then smoothed out. My wife drove off to work and tried starting it during lunch just to be sure and it started normally. Started normally for the drive home and started (and sounded normal) this morning without any problems.

Could the fuel injection be bleeding down during the days when it sat idle? If the battery is a little weak, can that cause a cranking-but-no-start situation?

Thanks for your help, Charles Scott