turboman38 Posted August 10, 2009 Share Posted August 10, 2009 I have the typical stage II cobb 93 map loaded with an SPT cat back, STi up pipe and shorty down pipe. I am getting a bad miss/stumble between 2 and 3 thousand RPMs. Even with the cruise on at 75 mph I notice it sometimes. I don't get any check engine light and it seems to run fine when accelerating hard. I also have run the rpms to 2500 while in neutral and I can hear the miss thru the exhaust. Plugs have less than 5000 miles on them. Any idea's on what could be causing this? This is an 05 with a 5 speed. Any help is appreciated. Have a great day! Link to comment Share on other sites More sharing options...
johnAWD Posted August 10, 2009 Share Posted August 10, 2009 When did it start? Have you tried reloading the stock map? Link to comment Share on other sites More sharing options...
turboman38 Posted August 10, 2009 Author Share Posted August 10, 2009 I have had it since new and attributed it to the ever so popular "Studder" issue as these cars are known for. It has become more noticeable since we installed the clutch. I recently changed the clutch but I wouldn't think that should have anything to do with it. I also have a vibration which sounds like a loose heat shield but have verfied none of the heat shields are loose so I don't know where the noise is coming from. The noise only happens when slowing down. Could the noise be causing the knock sensor (Do these cars have a knock sensor) to retard the timing or somethine? I didn't think I could reload a stock map with mods to the uppipe and down pipe Link to comment Share on other sites More sharing options...
qikslvr Posted August 10, 2009 Share Posted August 10, 2009 What clutch did you put in stock or aftermarket? I put in a lightweight flywheel when we did my new SPEC Stg2 clutch and I get a lot of grinding noise while coasting in certain gears. There are a lot of thing going on between 2K-3K RPMS. You may just be feeling a knock event or an injector misfire. Can you datalog? Let's kick this pig! Link to comment Share on other sites More sharing options...
turboman38 Posted August 10, 2009 Author Share Posted August 10, 2009 WRX flywheel with ACT heavy duty full face street clutch. I cannot datalog but would like to be able to. Where can I get the correct cable and software? I also am thinking about going to an open tune from Infamous1. I have emailed him so I can ask some questions on the phone. Link to comment Share on other sites More sharing options...
qikslvr Posted August 10, 2009 Share Posted August 10, 2009 WRX flywheel with ACT heavy duty full face street clutch. I cannot datalog but would like to be able to. Where can I get the correct cable and software? That different clutch setup is probably the cause of the noise. If it is a single mass FW and not a dual mass FW; it will amplify the gear noise from the tranny. Mine gets real loud with the STI Group N tranny mount installed too. It's mainly when coasting in gear. One easy way to tell is if you can make the noise stop by just bearly touching the gas pedal while coasting. If this makes the noise stop; then it's just the FW. As for the miss; many of us get some cruising knock at low loads/rpms that is very hard to tune out. Logging would be a good start and then getting Infamous to work out a tune for you would be better. Check this thread for logging using RomRaider(available at Romraider.com) and the Vag-Com cable: http://legacygt.com/forums/showthread.php?t=96737 This thread has info on flashing the ECU using the RR and ECUflash: http://legacygt.com/forums/showthread.php?t=110768 This thread has a link to the cheap cable some people are using: http://legacygt.com/forums/showthread.php?t=117895 Otherwise you can try to find a Tactrix v1 cable. Let's kick this pig! Link to comment Share on other sites More sharing options...
iNVAR Posted August 10, 2009 Share Posted August 10, 2009 ^-- like he said, if you have a laptop, start datalogging with RR and find out about the knock. but for now, try tossing on a 91 octane stage 2 map and see what happens. my cobb stage 1 93 octane was knocking even though i was filling up with 93, so i backed down to a 91 map while still using 93 gas (which loses 5hp according to cobb) and the knocking is gone. Link to comment Share on other sites More sharing options...
turboman38 Posted August 10, 2009 Author Share Posted August 10, 2009 Thanks for the reply. I will try the 91 map with 93 octane to see if it makes a difference. Link to comment Share on other sites More sharing options...
turboman38 Posted August 10, 2009 Author Share Posted August 10, 2009 Do you think it's knock? Knock is a bad thing as I have blown head gaskets with my Turbo Buick because of knock. I didn't think the Maps COBB wrote were aggressive enough to cause knock if using 93 octane. Link to comment Share on other sites More sharing options...
iNVAR Posted August 10, 2009 Share Posted August 10, 2009 mine was definitely knocking as confirmed with datalogging. went away 100% when i switched maps and reset the ecu. (actually, still had a little shift knock, but that's to be expected i think, and fine since it's ultra low load) here's my own thread if you're interested: http://www.legacygt.com/forums/showthread.php?t=116672 Link to comment Share on other sites More sharing options...
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