Subaru Outback 2001 LLBean Edition won't start

I have a 2001 Subaru Outback v6 with 111K miles on it. Yesterday, when I put the key in to start the car, it tried to start but unsuccessfully. I had to tow the car to the mechanic. He looked at it and can’t find anything. Starter, sparks, and batteries were all OK. He put the computer on and there were no error codes. Somehow he got the car started (he didn’t know what caused the car to start). He had the car overnight and the car still starts in the AM. I got the car back but,am very nervous and afraid the car won’t start while I am out. Any idea what can be wrong?

First, I assume that by “tried to start but unsuccessfully” you mean that the car cranked over just fine, but never actually started running. Clarify that b/c turning the key and not having the engine crank at all is a whole different kind of problem.

“Starter, sparks, and batteries were all OK”

What about the fuel pressure? Was that checked?

Intermittent problems are a complete pain b/c you have to sort them out while the problem is actually happening - which is why your mechanic couldn’t figure it out.

If the crank is good and healthy (RRRR.RRRR.RRRR.RRRR.RRRR - or however you want to put it), but it won’t start you either lack fuel or spark. You can arm yourself for the next time it happens.

If this all sounds like Greek ask your mechanic to show you. Go to an auto parts store and get a can of starting fluid and a spark tester. If this happens again, first just turn the key to run, but not all the way to start (just to where the dash lights come on) and listen. You should hear a rather quiet 2-3 second hum probably from behind you. That will be your fuel pump. If you don’t hear the hum then your mechanic has to troubleshoot the power supply to the fuel pump and the pump itself.

If you hear the hum, turn the key to run/off/run/off/run/off about 5 times or so, waiting for the hum to stop each time. Then crank it. If it fires right up then you should probably replace the fuel pump.

If you do that and it doesn’t fire up then blow some starter fluid into the intake (this is what you might ask about). Then try and if it fires, even for a couple of seconds, then your mechanic needs to troubleshoot the fuel pump (and probably replace it, but how old is that fuel filter?)

If none of that works, hook up the spark tester and check for spark (another thing you might want to ask about but a tester should come with instructions). You need a good, strong, healthy spark. If you don’t have one then the mechanic needs to troubleshoot the ignition system.

This at least gets you down to one of the two systems.

When I turn the key all the way to start, I can hear the normal start sound (I guess the rrr.rrr.rrr sound), but, the car never catches. When AAA came, the guy listened to the sound and said it wasn’t the battery. When the mechanic got the car, he wasn’t able to work on it until the afternoon. He also couldn’t start the car and had to push it into the garage. His repair note said the fuel pressure and ignition spark were within spec. He wasn’t sure why the car suddenly started after several attempts.

I know I am due for an oil change (it has been about 4 months and almost 3000 miles since my last change). But, I didn’t think the oil filter will be that dirty. However, I mainly drive locally…start, drive a mile or two, park, etc.

I hope the additional information is helpful. I will get the starting fluid and spark plug tester so that I am prep the next time this happens. Thank you.