Doing some work on this 02 WRX that was brought to me last week. They stated that the plugs had not been changed since 55k and the odometer has 166k on it so I told them they needed to be changed. I look up the OEM NGK plug and get 4 of them from advance auto.

 

Firday evening, I change the plugs on cylinders. Started it up and it sat and idled just fine in the driveway for 15 minutes while I put my tools up and went in for the night. Today, I changed the plugs on 2 & 4 and re-oiled the filter element on the SPT intake it has. Buttoned everything back up, battery, washer tank, etc. Now, the thing does not want to idle and is missing under normal load. It did throw a CEL for a misfire on all 4 cylinders.

 

Out of ideas, I put the original plugs for cylinders 2 & 4 back in and that had no effect. I am baffled. I know that the filter oil can accumulate on the MAF sensor and cause a running issue. Could that be causing this misfiring issue?

Checked all the wire connections twice? MAF sensor plugged in? ( I would expect there to be a code if not). I've always gone light on the oil with wet filters on cars that have a MAF sensor like these. It might not hurt to check and clean the MAF.

 

How about vacuum hoses? Intake clamps tight? No hoses missing from the intake tube/airbox? Breather hoses all attached on the valve covers, block, PCV valve? Any cracks or splits in the tube or boots?

In my not-so-expert, expertise, I've only ever seen a 4 cylinder misfire from jumping time or soaking the plugs.

In my not-so-expert, expertise, I've only ever seen a 4 cylinder misfire from jumping time or soaking the plugs.

 

As have I, that's what's got me baffling and I find it hard to believe I got 4 plugs bad out of the box. Planning to clean the maf this evening when I get home.

that filter may be a dry-flow that is washable, or it's disposable. If it is SPT and not an AEM or K&N replacement media, it's about $40-$50 to replace.

 

I don't think it's oiled. At least, not supposed to be cleaned and re-oiled. A new one may have some kinda 'treatment' on it.

 

not certain though.

Edited April 16, 201213 yr by 1 Lucky Texan

that filter may be a dry-flow that is washable, or it's disposable. If it is SPT and not an AEM or K&N replacement media, it's about $40-$50 to replace.

 

I don't think it's oiled. At least, not supposed to be cleaned and re-oiled. A new one may have some kinda 'treatment' on it.

 

not certain though.

 

Well, I learned something.... the hard way. I am going to clean the MAF when I get home tonight and see what it does and start trying to get this thing running better.

 

http://forums.nasioc.com/forums/showthread.php?t=1282520&highlight=clean+spt+intake

 

http://forums.nasioc.com/forums/showthread.php?t=1373545