2004 Subaru Forester starting and idling problems

ddm2016

I have a 2004 Subaru Forester. It will try to start but won't. It's done this quite a few times this past month. I was told to put some kinda cleaner in my gas tank. Tried it. Thought it worked cause car was fine for the next couple days. Then today it wouldn't start again. So I had to hold break down and gas pedal at the same time, cause when I'd come to a stop it wouldn't idle. It would just die. Finally made it home. Tried to start and it cranked right up. Really need some help.

sennat

(I am not a mechanic, so derate this accordingly.) My experience with my 2003 Forester may be helpful. I was also having intermittent starting problems, cranking a lot and having to push the gas pedal until the idle smoothed out. The rough starts were also triggering cylinder misfire codes, I got tired of resetting them eventually and just lived with the Check Engine light. I think the codes were a symptom of the starting problems. Once running smooth everything was fine.
Anyway, I eventually focused on the idle air control valve. This is a little motor that pushes a cone into a small airway on startup, then retracts it during run. It's easily accessible right on top, held in by two small screws, with a wiring harness attached. Apparently the screws are easily damaged so be careful when removing. The thinking was that the drive mechanism was getting sticky leading to intermittent start problems.
I first tried cleaning the cone/shaft and hosing it down with WD40, but the lube didn't get into the drive since the mechanism was fully retracted. There was some improvement, so recently I went further: removed the unit, reconnected the wiring connector, turning the ignition key to On (NOT engaging the starter). You'll see the cone extending, then retracting partially. (NOTE: every time you do this, it will extend farther, eventually coming apart. It seems to be on a clutch mechanism so you can prevent this by keeping a finger on the cone to limit the extension. I rigged an equivalent with some duct tape.) When extended, I hosed it down again with WD40, this time wetting the interior of the drive shaft. It has started flawlessly since.
I hope this helps...
Sennat

sennat

Update: Probably nobody read my previous comment; hopefully not, as my diagnosis was wrong. Problem was intermittent so I attributed a temporary improvement to my efforts to lubricate the idle air control. Actual problem was a malfunctioning fuel pressure regulator. At least it wasn't the fuel pump.
Sennat