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-   -   Misfire and shuttering acceleration (http://www.wrxtuners.com/forums/f72/misfire-shuttering-acceleration-33241/)

kamikaziboarder 11-07-2012 12:35 PM

Misfire and shuttering acceleration
 
I'm trying to get down the root of the problem. This is for a 2005 Subaru WRX with 93k miles on it.

I haven't driven my car many miles in the past months. Probably 1,000 miles over 7 months. I try to take it out once a week for about 15-20 mile drive.

I recently starting having problems. I first noticed that my car would shuttered only under heavy acceleration. My CEL would flash a few times and go off. I first checked the code. It had a misfire on cylinder one. I figured my injectors were getting plugged up since my car sits a lot. I put fuel injector cleaner through. I also cleaned out the purge valve. My code cleared for cylinder one. I still have the acceleration problem. This only happens under heavy acceleration, my car shutters once it moves up into the higher RPMs. If I gradually accelerate, no issues. Now, I'm having a misfire on cylinder 3.

My car is completely stock. No replacement parts besides general maintenance items.

kamikaziboarder 11-07-2012 12:39 PM

Just to add. I also swapped out the coil packs and spark plugs to see if that made a difference. My codes didn't change based on swapping parts around.

pzr2874 11-07-2012 01:25 PM

And do you put fresh gas every month or so?

kamikaziboarder 11-07-2012 02:06 PM

I do, I never fill up the tank all the way in order to make sure I can put fresh fuel in every once in awhile. I run it down to about 1/8 of a tank, then fill it back up to a 1/4.

pzr2874 11-08-2012 05:57 AM

Check the fuel filters and injectors. Have you done your timing belt/pullies/water pump/thermostat yet?

kamikaziboarder 11-08-2012 11:49 AM

Alright, thanks I'll take a look at that. I haven't done any of that maintenance yet. I was reading the manual saying that the timing belt is at 120k.

I haven't done anything to the water pump or thermostat, just full radiator flushes every 30k. I'm not having any overheating problems.

BoostinChick 11-08-2012 11:51 AM

When you swapped the parts around, did the misfire move? Are you boosting at all, or is the cut out that bad? Only other thing I would recommend to check is your vac lines. Maybe one is dry rotted from sitting?

Timing belt is @ 90k btw.

kamikaziboarder 11-08-2012 12:07 PM

The misfiring didn't move to another cylinder. The boost cuts in and out. So it'll kick on for a second, then the car would shutter. It would kick back on, do this about 6-7 times up to the redline. It only happens when I have really push it. If I gradually accelerate up to redline, its smooth and boosting.

I checked out all the lines I could get to. No cracking of any sort.

BoostinChick 11-08-2012 12:18 PM

Almost sounds like a bad MAF....I would check that next if your fuel checks out okay.

kamikaziboarder 11-08-2012 09:37 PM

Wouldn't the bad MAF trigger a code and cause the car to idle rough?

I took the car out of a drive today. The car only shutters when its boosting. At lower RPMs with the pedal to the floor, it accelerates smoothly. I will begin to hear the turbo start spooling up. Get the burst of power, then it shutters. I also hear what it almost sounds like, air escaping. I'm starting to wonder if I have a bad air by-pass valve. Could it pre-maturely failing?

pzr2874 11-09-2012 05:44 AM

Check for boost leaks. under the TMIC first.

kamikaziboarder 11-10-2012 10:22 AM

No luck. Everything looks good.

Gaspo 11-25-2012 06:34 PM

my car is doing the exact same thing. i just changed plugs. the old ones were shot and it seemed to help a little. doesnt do it much in first gear but 2-5th is horrible. when you find out what your issue is, please let me know! i just bought the car yesterday and gotta get this figured out.

General-Leo 11-25-2012 11:09 PM

I'm sure I will get a little bit of hate for this but... I was having the same problem on my RX8 like a week ago right after I filled up the tank. before I filled up I was having a rough idle problem, but after I got gas the car completly died on me while driving down the highway, and would not restart... to get to the point after trying a few things myself I ended up taking it to the shop. They ended up replacing the plugs and wires, the coils, and the fuel pump (because they broke it). they also came to the conclusion that the gas in the tank was contaminated, so they drained it (hints the broken pump) and filled it back up. The shop told me that it was a combination of all of the problems together making the car act like it did. when I got it back it ran like a CHAMP (or as well as expected for an RX8) haha. When you take the car to get gas are you going to the same place every time? maybe their gas is slightly contaminated? maybe so octane booster would help?

And just to clarify to hopefully reduce the amount of flame I will receive I have a 2013 wrx on order, currently waiting for it to get to the dealer, I am not just randomly a member of a subie forum.

Gaspo 11-27-2012 08:20 AM

it sounds like we have the same problem, but my car isnt throwing a code. i replaced plugs, swapped my bov with a stock bypass valve, checked the y pipe under the tmic and all charge pipes for leaks/cracks and couldnt find anything.


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