n_hall

a couple weeks ago i repaired my afm and replaced my fuel pressure regulator. my car ran better than it ever has in my ownership of it. before that it would sound like it's running on 3 cylinders, but noid light and spark plug light testing showed that all four were getting fuel and spark.

fast forward a couple weeks and it started to sputter anywhere between 2k and 4k. and it also switches to the 3 cylinder running normally when i try to accelerate a little faster than a soccer mom in a minivan. it will do that until i let off the gas, it will then run normally but probably sputter.

it's starting to get on my nerves every time i drive it. i was trying random things trying to fix it. today i replaced my afm with a used one on ebay, but it's running the same. i tried running it with the o2 sensor unplugged and it runs the same as with it connected. could it be the o2 sensor? anyone have any ideas?

thank you,
nick

Lizard944

Sounds familiar. Mine turned out to be a bad injector. Measure the exhaust manifold outlet temperatures for each cylinder with an infrared thermometer gun. The one running cooler is the faulty cylinder. You can try a quick fix by getting a socket extension, put it against the suspect injector, and tap it with a hammer while the engine is running. Don't beat the **** out of it, but firm enough taps to send a shock wave through the injector to free it up. If you don't have an IR thermometer, and aren't sure which cylinder is faulty, you can try this trick on all of the injectors and see if you get improvement.
--Lizard

krystar

man nick u really are just not having a good time.

i'm in the city now..i'm gonna go back to my place tomm. i think i have a couple extra injectors for u to try

n_hall

i had them repaired by witchhunter, i wouldn't think they'd go bad already. it's been less than 4 months

MikeV

Sounds like a problem i had a few years ago. Had a dead skip under load, ran fine at idle. Good compression, leakdown numbers were good, replaced injector, plug, wire, had new AFM. Turned out to be a broken valve spring.

n_hall

someone on pelican also said it might be a valve spring. i take it there's no easy way to do the springs. if i replace them i'd end up doing the timing belt/water pump, and all the top end gaskets right?

n_hall

yuliang, can i take you up on that offer? i put fuel injector clean in the tank and now it's running on 3 only, back to the same problem i've been trying to fix since i got the car. i tested the wires with the noid light again, and i'm getting signal to all four. i really doubt that it's the injector though. i had them cleaned by witchhunter and they all passed. and after that it still ran on 3. so i most likely have to do a rebuild.

krystar

i'm leaving for indy tomm. but if u come by on saturday, a bunch of friends will be using my garage. one of my friends knows my 944 inside out so can prob help figure something out.

if u want to take off the cambox to inspect, that's not such a big deal. u don't have to remove the belt, just loosen it so it can slide off the cam gear.

pm'd u my address.

Lizard944

I still wouldn't rule out an injector. I did the same thing and sent out injectors for servicing. After returning with a clean bill of health, I installed them and had the same "sputtering" problem. Many part swaps later, I revisited the injectors with more thorough tests (see my previous post), and discovered the bad injector. The injector would start acting up only after several minutes of driving which is probably why it got past the function tests. Try the injector "spanking" that I described to see if it improves. Just make sure you use a metric hammer!

n_hall

yuliang, can i get a phone number to let you know if i'm coming, and so you can get a response faster?

krystar

nick...i guess u didn't come over. everything ok?

i already was on the road by the time u posted the last message hehe.

n_hall

i think i've given up on her. i'm looking into getting a wrx now, but it's going to be hard because i've only had this job for a few months now.
it saddens me to think of giving up on her.

krystar

awww why? we can get her running good....just need some extra spare parts to figure out what's wrong