shady02 Posted February 26, 2012 Share Posted February 26, 2012 whats up everyone, I'm new to the site and have been doing nothing but reading through threads so figured is time to post one. ok so i got a 07 lgt limited auto with 83k. been idling and running a bit rough lately. while driving maybe 40-55mph if i hit the gas and let go the rpm will automatically drop to about 600 then bounce back to about 1100? also after ar had warmed up and when i put in reverse or drive idle will drop pretty low almost feels like it wants to stall but doesn't. just put new iridium laser plugs about 2 weeks ago and car came with spt air intake. I'm really not big on mechanics but have been searching like crazy to try to learn. all input is appreciated. Link to comment Share on other sites More sharing options...
NickTej22 Posted February 26, 2012 Share Posted February 26, 2012 The car well idle higher when it's cold, like in the morning, or first start of the day. Then drop. iridiums trend to make the car idle "lower" than other plugs because old nasty plugs seem to make a car idle higher. As for the idle doing low and going higher, when a load is applied it will idle higher, then when the load is off it will go back down. For example your cooling fans, when driving in the city, sitting at a stop they may kick on and raise your idle. If the cats idling around 600ish (700 seems ideal without loads applied (like your a/c) then you should be good. But keep a close watch on your idle so we know exactly how much fluctuation there is. Sent from my MB855 using Tapatalk Link to comment Share on other sites More sharing options...
bmx045 Posted February 26, 2012 Share Posted February 26, 2012 look in the walkthrough forum for the intake manifold gasket issue Link to comment Share on other sites More sharing options...
shady02 Posted February 26, 2012 Author Share Posted February 26, 2012 so car feeling like it wants to stall sometimes could be the iridiums? and as for rpm needle dropping to 600 and bouncing to 1100 on its own after letting go of gas, normal? Link to comment Share on other sites More sharing options...
bmx045 Posted February 26, 2012 Share Posted February 26, 2012 no. the iridiums dont cause this in these cars atleast. if youre in drive and you blip it gas for a second from a stop it can dip low then come back up. Link to comment Share on other sites More sharing options...
shady02 Posted February 26, 2012 Author Share Posted February 26, 2012 right. and i have read your walk through post but pictures don't come up. i also don't have any check engine light but could codes still pop up? Link to comment Share on other sites More sharing options...
bmx045 Posted February 26, 2012 Share Posted February 26, 2012 if it idles exeptionally rough during cold starts up until the engine is warmed it could be the manifold gaskets, you may not get a cel. the car will want to die at red lights and idle really rough while the engine is cold. usually happens in outside temps below 40* Link to comment Share on other sites More sharing options...
shady02 Posted February 26, 2012 Author Share Posted February 26, 2012 car also stalled on me once when i threw it into reverse bet hasn't done it again yet. ill have to get these manifold gaskets checked out I'm just not really a diy kinda guy yet nor have the tools. Link to comment Share on other sites More sharing options...
shady02 Posted February 27, 2012 Author Share Posted February 27, 2012 so i put the car in triptronic to make sure it just wasn't shifting. while driving when i let go out the gas the rpm will drop to about 600 then bounce to like 11-1200 on its own? Link to comment Share on other sites More sharing options...
Max Capacity Posted February 27, 2012 Share Posted February 27, 2012 PM climberD or BAC5.2 They are really good with some problems. I'm not good with automatics, but when my 05 had low idle issues and stalling it was the intake o-ring seal/gaskets. It's a common issue with these cars when it's cold. I do believe the cars will drop to idle and then bounce back up for a couple seconds before they settle at idle during some driving situations. I think my 09 does that. I also had my Tuner set the idle higher in my 05 when the car was on the dyno last Aug. 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...
shady02 Posted February 27, 2012 Author Share Posted February 27, 2012 Would the intake gaskets make it seem like its knocking louder? Idle seems to be a lot louder/harder Link to comment Share on other sites More sharing options...
bmx045 Posted February 27, 2012 Share Posted February 27, 2012 take a video of the noise Link to comment Share on other sites More sharing options...
shady02 Posted February 27, 2012 Author Share Posted February 27, 2012 I'm on my iPhone. Do I gta go threw photobucket or something? Not familiar with this Link to comment Share on other sites More sharing options...
bmx045 Posted February 27, 2012 Share Posted February 27, 2012 post it to the youtubes Link to comment Share on other sites More sharing options...
Max Capacity Posted February 27, 2012 Share Posted February 27, 2012 Would the intake gaskets make it seem like its knocking louder? Idle seems to be a lot louder/harder Knocking is not a good thing. The rods and pistons should be quiet in these cars. The older ones had piston slap when cold. I swear my 05 sounds better at idle after I start it cold then my 09 does. I think the 09 has louder injectors. Both have very little rod, bearing or piston noise. 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...
bmx045 Posted February 27, 2012 Share Posted February 27, 2012 my 08 developed rod knock only at idle in D. cant hear it while accelerating. nonetheless the bearings suck in certain years. new '12 sti block goin in this weekend Link to comment Share on other sites More sharing options...
shady02 Posted February 27, 2012 Author Share Posted February 27, 2012 Prob not knocking but rods and pistons seem to be louder then normal at idle. Idk I'm bringing it to a Subaru place to get checked over on Wednesday so well see what they say. And I also need to get a turbo gauge to make sure it's boosting correctly as well. Link to comment Share on other sites More sharing options...
bmx045 Posted February 27, 2012 Share Posted February 27, 2012 if your rods are noisy, its rod knock Link to comment Share on other sites More sharing options...
shady02 Posted February 28, 2012 Author Share Posted February 28, 2012 Awesome. Link to comment Share on other sites More sharing options...
bmx045 Posted February 28, 2012 Share Posted February 28, 2012 post a video Link to comment Share on other sites More sharing options...
shady02 Posted February 28, 2012 Author Share Posted February 28, 2012 Still at work and shit sucks on the phone. Got a video on the idle bouncing I'll try to post when I get out. Put it on YouTube and then just paste the link? Link to comment Share on other sites More sharing options...
bmx045 Posted February 28, 2012 Share Posted February 28, 2012 Yes jesus Link to comment Share on other sites More sharing options...
shady02 Posted February 28, 2012 Author Share Posted February 28, 2012 Amen. Link to comment Share on other sites More sharing options...
shady02 Posted April 15, 2012 Author Share Posted April 15, 2012 Link to comment Share on other sites More sharing options...
Max Capacity Posted April 15, 2012 Share Posted April 15, 2012 Have you cleaned the MAF sensor yet ? My 05 would do that but since I replaced the o-rings between the intake and TGV's that stopped it and the clean MAF made a big difference in cold engine performance. 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...
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