ATTN: Suby people - misfire diagnosis

[Maengelito]

WARNING: NON-BMW CONTENT AHEAD

Question up front: Are fuel injectors on a Subaru a PITA to swap? I've read it takes several hours and the intake manifold might have to come off?

Background: A couple of months ago, the Foz had developed a bit of a hiccup at idle. I got a solid CEL and the flashing cruise light which turned out to be P0302 - misfire on cylinder #2. I went ahead and changed all the plugs since I don't know if its ever been done. I also swapped the coilpacks for cylinders #2 and #4 and put di-elec grease on all the connections. The car ran like a top afterwards. :thumbup: Then a couple of weeks ago, the Foz started to stumble at idle again, same solid CEL and flashing cruise light. Pulled the code and it turns out to be P0302 again. At this point, I figure its the fuel injector since it didn't follow the coilpack. Before I dig into it while its 100deg outside, could it possibly be something else that I haven't even thought of? If swapping injectors is a huge pain in the ass, should I just replace them the first time instead of swapping them and then having to do it all over again if that confirms that the injector is the problem?

Some random questions/thoughts:

Why would the car run great for a few months after changing the plugs if that wasn't the problem in the first place?
Is there a good tutorial on NABISCO/Scoobymods/etc. on swapping injectors? I haven't been able to find one.

[Apoc]

could it possibly be something else that I haven't even thought of?

Maybe it's really a VAG.

[D_Eclipse9916]

Not saying that you may not have a problem. But lots of turbo cars develop misfires, and then the code causes the car to run like crap until you reset the ECU. Trying resetting the ECU and see how it is, 99% of the time its just a random misfire (at least in my experience on helping friends suby cars and my own dsms.

Then again, you also want to find out whats wrong. My DSM did it twice, and then disappeared for years. hrugs:

[Maengelito]

I fucking hate you both. You bring up VAG and DSM as the first two replies. My car is probably on fire in the driveway as we speak.

On a brighter note, my Washington Caps plates arrived in the mail this week

[ScottyB]

hate to ask since changing plugs on a turbo suby is a PITA, but do you recall them being gapped properly?

as to changing injectors, not sure. if i see a good tutorial i'll post it up though.

[ViPER1313]

What does it do when you unplug the MAF?

[Maengelito]

So when I go out there today to fiddle with it, of course its running really smoothly. I still got in there to make sure the contacts were clean and put some grease just in case. The good news is that I don't think I'll have to take the manifold off to get to the injectors. The bad news is that it looks like the injectors are secured on by torx bolts and they're pretty corroded.

Scotty, the plugs had the proper gap when I installed them. Adam, I'm not sure what happens when I unplug the MAF but I'll try that if it starts acting funny again.

[ViPER1313]

Just thinking you should eliminate the MAF first because it is so quick / easy to check. I have heard of engine computer's diagnosing bad MAF readings as cylinder misfires, even consistently on a single cylinder (common on 2.0 Jettas for example...)