Zac88 Posted April 10, 2014 Share Posted April 10, 2014 I still find that my 05 GT has a "rough" idle, as in its not perfect but you can definetly feel it. I'm hoping others will chime in on how theirs feel. I can feel it more so when I have my hand on the shifter. I have replaced: -Spark plugs -IM gaskets -Injectors -Both O2 sensors No vacuum leaks from what I can find, I barely burn any oil which is great considering I'm over 170,000km Edit: I do have a Spec LWFW installed if that has anything to do with it. When I had my intake manifold off I replaced the turbo inlet and was able to check turbo shaft play and there was barely any play if any at all. Everyone that has ridden or driven my car says its pulls hard and cant feel any drivability problems. I just dataloged the AVCS and OCV to make sure they were functioning properly and it seems to be. My next step is to do a compression test to see if thats the problem but I would rather avoid that cause as we all know its a pain to do and I just did the spark plugs in January. Link to comment Share on other sites More sharing options...
idiot4hire Posted April 10, 2014 Share Posted April 10, 2014 I had a bad cam shaft sensor that was screwing with my idle for a while before the cel popped on Link to comment Share on other sites More sharing options...
Zac88 Posted April 10, 2014 Author Share Posted April 10, 2014 I had a bad cam shaft sensor that was screwing with my idle for a while before the cel popped on popped both of them out and cleaned them, if one was bad would it have shown up in my AVCS datalog? Link to comment Share on other sites More sharing options...
Zac88 Posted April 10, 2014 Author Share Posted April 10, 2014 One thing I forgot to mention was that the RPM needle doesnt fluctuate at all and even looking at the AP logs the rpms dont very much at all. Also popped off the oil filler cap and idle and no smoke comes out so theres no excessive blow by. Link to comment Share on other sites More sharing options...
idiot4hire Posted April 10, 2014 Share Posted April 10, 2014 You clearly have my knowledge then I so I'll leave it to someone else. I can only share my personal experience Link to comment Share on other sites More sharing options...
PtPixel Posted April 10, 2014 Share Posted April 10, 2014 H4's aren't as well balanced as most other engine configurations (better than I4 but not as good as V6/V8) so the idle is a little more bumpy than other vehicles. You shouldn't be seeing anything too rough, just the odd small shake/bump. In contrast [to the I4], the flat-4 has much less secondary imbalance at the expense of larger rocking vibration, that causes it to rotate back and forth around a vertical axis. This is because the cylinders cannot be directly opposed, but must be offset so the connecting rods can be on separate crank pins, which results in the forces being slightly off-centre. The rocking vibration is usually not serious enough to require balance shafts. Link to comment Share on other sites More sharing options...
GTborn01 Posted April 10, 2014 Share Posted April 10, 2014 Check your coil pack wires. One of mine was almost disconnected and caused a rough idle Link to comment Share on other sites More sharing options...
GEE-OTTO Posted April 10, 2014 Share Posted April 10, 2014 The 05 came stock with a DWFW you put in a SMFW on the 05/06 specifically there have been cases where this changes causes issues. The Spec is much lighter than the DMFW so it could be causing issues with your crank and cam triggers, tough to nail it down since you seem to have covered all bases and the car functions normally. Link to comment Share on other sites More sharing options...
Max Capacity Posted April 10, 2014 Share Posted April 10, 2014 Have you cleaned the MAF sensor ? The Spec LWFW is 17lbs, the stock DMFW if I remember right was 27lbs I think m sprank knows for sure. My car idle no different after the Spec LWFW was installed. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Zac88 Posted April 10, 2014 Author Share Posted April 10, 2014 cleaned the MAF a few times. Link to comment Share on other sites More sharing options...
Zac88 Posted April 10, 2014 Author Share Posted April 10, 2014 My friends STi idles the same as mine. Maybe im just going crazy lol Link to comment Share on other sites More sharing options...
Max Capacity Posted April 10, 2014 Share Posted April 10, 2014 Who's tune is in the ECU ? 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
rob-2 Posted April 10, 2014 Share Posted April 10, 2014 My friends STi idles the same as mine. Maybe im just going crazy lol You are! It bothered me for a while and now I live with it. Link to comment Share on other sites More sharing options...
Zac88 Posted April 10, 2014 Author Share Posted April 10, 2014 COBB OTS stage 1 93octane Link to comment Share on other sites More sharing options...
GTborn01 Posted April 11, 2014 Share Posted April 11, 2014 ^that could be part of the problem because the Cobb OTS tunes are so dated now. Link to comment Share on other sites More sharing options...
PtPixel Posted April 11, 2014 Share Posted April 11, 2014 ^that could be part of the problem because the Cobb OTS tunes are so dated now. It's still the same engine the tune is designed for? OTS tunes are bottom tier tunes though Link to comment Share on other sites More sharing options...
GTborn01 Posted April 11, 2014 Share Posted April 11, 2014 It's still the same engine the tune is designed for? OTS tunes are bottom tier tunes though Yes but I was talking to one of the tuners at Cobb (Surgeline is about 10 minutes from my house) and he said the lgt maps are so old that a pro tune is going to be much better. Doubt it would cause an issue but it's worth mentioning just in case. Link to comment Share on other sites More sharing options...
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