Within the last week my '99 SUS with a 2.5 DOHC with 195,xxx on the ODO has been missing on cylinder 3. Now before anyone mentions the spark plugs, yes I'm due for plugs which I plan on replacing this week. This all started a few nights ago when I was low on fuel. I've noticed before that when I get low on fuel (low as in on "E" or just below) my engine kind of starves for fuel.  But anyway, I put gas in my car and started driving which is when the misfire started. I've noticed it mostly starts after I've driven it for 10-15 minutes or so.  If anyone could give me insight as to what else might be happening, that'd be great. Thanks.

Plugs and wires.

 

Put a fuel filter in it if that hasn't been done recently.

Plugs and wires were done at the same time at 164k. Wires are STI (spark transfer international). Did the fuel filter about 15k or so ago.

Try swapping number 3 plug wire to a different cylinder and see if the misfire follows.

 

What kind of plugs were put in at 164k?

Getting the #3 plug out was enough of a POA... Not sure if I'd want to swap it with another! I think NGK platinums were put in. I haven't had the misfire since Sunday when I pulled the plug. Hopefully it will stay that way until I have a chance to put new plugs in.

Getting the #3 plug out was enough of a POA... Not sure if I'd want to swap it with another! I think NGK platinums were put in. I haven't had the misfire since Sunday when I pulled the plug. Hopefully it will stay that way until I have a chance to put new plugs in.

All the plugs on a DOHC 2.5 are a PITA to change. Been there........done that more then once. I am thinking that new plugs, and maybe new wires will correct your problem. Unless you spent about $50 for Subaru OEM wires, or $50 for high end end after market wires, you are likely to have plug wire issues. Subarus do not like cheap plug wires!!

I think STI wires were about $80 a set last time I checked.

 

The suggestion was to swap the WIRE to another cylinder (move number 3 to 1 and vice versa) and see if the misfire code changes to that cylinder.

 

Platinum plugs do not have a good reputation among Subarus.

If you must use them though, they have to be Double platinum (platinum coating on both the center electrode and the ground electrode) otherwise the wasted spark ignition system will mess them up.