So just now, on my way home from class, I noticed that my acceleration is sluggish and rough. It is less noticeable at higher revs, but very noticeable at lower revs when you give it gas. It makes the car shudder and you can feel it even more in the steering wheel.

There is a very noticeable "putt-putt-putt-putt" sound coming from the tail pipe at idle and the tach seems twitchy.

On a side note, it has taken a split second more for the engine to catch when starting, lately.

 

Sounds like injector time...

 

That was my first thought...there goes any extra money I would have...

What is the normal resistance for a VG?

 

11-14 ohms
and it sounds like injector time to me.
though how old is your tune up?

 

The car ran mint as of a few days ago...C'mon, Brian, I am meticulous about that sort of thing. The only thing I have never replaced would be the O2 sensor, but these symptoms don't seem to point to that being the culprit...

The fact that I can hear a uniform-interval "putt-putt-putt" in the idle sounds to me like one injector, in particular.

 

its an injector, or possibly a gremlin.

Ive been having injector trouble over about the past 2 weeks, but last night I drove and it was working perfectly, not a hint of any issues! I was shocked, as I had already replaced 4 injectors on this engine and none of the gonners managed to recover after failing outright.

 

Could also be the injector connectors. My 240 has that problem. I need to get some new ones. Should be a few bucks a piece. Just wiggle the connectors and take them off and clean them and put some die-electric grease on them.

If thats not the case with mine, I'm getting 3 more (already have 3) 240sx injectors and making them fit (making a fuel rail etc) my max. I can get them for $3 piece and they are reliable.

~Alex

 

Bummer, sounds like I'm going to need injectors myself.

 

even meticulous people can overlook the obvious.
so how old is the tune up

 

Not too old...so it hasn't been acting up almost at all since I posted this morning. I drove it to a friend's house to test the resistance and it ran perfect the whole time. It will sometimes putter a bit at idle, but as soon as I drive it for a minute or so it's fine. I'm sure it will become more of a problem, in time...so I'll wait until then and see what happens.

 

That sounds familiar, for about the past month and a half. Would failing injectors also cause a drop in mpg?

 

Check your O2 sensor and change your CTS.

 

I was going to say I had run the diagnostics and it didn't beep at me, but I was thinking there was a space on the diag for the O2 sensor, but looking at the instructions I guess I was wrong. An O2 sensor should be about $100, $120 right? Is there a test to check functionality I could conduct? I don't even know what you mean by CTS. Thanks.

I think damn the idea though, like I just posted here, I'm trying to buy a new one, I just can't find one with options.

 

new o2 is like $60 to your door (maybe less )

our injectors have been known to fail then fix themselves, then fail again repeat etc... I had it happen to me, but they ended up staying fixed

 

So O2 sensor first. Hope that's all, otherwise I might have to keep it as a parts car after all. This is getting bad.

Would a '99 SE 5spd really be worth it? So much less sexy.

 

The rough running problem is already becoming more frequent...I am off to Milwaukee for the weekend with a buddy who is getting yet another JDM 2.0 subie motor installed in his swapped 2.5RS at a particular shop...this shouldn't have to be happening in the first place...

He was on his way to sell it and blew yet another fresh motor (under 10K miles)...111% injector duty cycle + 20 lbs of boost still boosting strong + 173mph = KABOOM!!!

Anyway, I will worry about testing the resistance of the injectors when I return...

There is a good chance I will be driving his newer car, '05 STI w/ Cobb programmer all the way back from Milwaukee ...I guess there is an autocross he wants to run, so might as well...

Enough with the OT stuff...Question: it seems as though only one injector is bad (which one is yet to be determined), so should I just replace the one bad injector, the entire bank (3), or all of them at once (6)?

 

Save your money and go for the bad one. If yet another goes bad in the future you will

A) know the symptoms right away and wont let it drag on
B) already have some experience changing it, and will do a better job than before

 

When the injectors fail, do they get stuck open or closed?

 

Both..In my case a few months ago,one of my rear injectors itermittently stuck closed....

 

Hmm...I see...did you just replace the one, or do you do several at a time? And how many times have you had to replace injectors?

 

I got a used set of six still in the rails,then just replaced the rear rail where the bad one was..

This was the first injector to ever go out since i've owned the car[2000]

 

Well hopefully that is a good indication of the other injectors not being ready to

Why did you swap the whole rail in? Is it just easier than swapping individual injectors?

 

IMO,it is much easier to just swap the rail out if you have a used set handy,that way you dont have to mess with all the o'rings-n-crap...

 

I have confirmed that injector #4 is not operating...it is stuck closed...2 new fuel rails complete with injectors on the way...that is all.

 

Oh, just to clarify, cylinder #4 is the middle one on the front bank.