breadstick Posted June 13, 2013 Share Posted June 13, 2013 I couldn't find much about a low idle in a search, but my car idles at about 450-500 RPM when it's warm. When I first start it before it warms up, it idles like it should and drives and idles smoothly. Once it warms up, the idle drops and I can feel it start shimmy just a bit at idle. It seems like a vacuum leak but I can't find one. Any ideas? Link to comment Share on other sites More sharing options...
chimera Posted June 13, 2013 Share Posted June 13, 2013 Possibly a dodgy O2 sensor as they can mess with idle. It's not far off normal though mine sits 600-700rpm Link to comment Share on other sites More sharing options...
Drogos Posted June 13, 2013 Share Posted June 13, 2013 vacuum leak? Link to comment Share on other sites More sharing options...
Max Capacity Posted June 13, 2013 Share Posted June 13, 2013 Dirty MAF sensor ? Could be a few things. Does it run good when your on the throttle ? I guess you have no CEL's ? Have you cleaned the battery terminals lately ? It's just something that's good to do every now and then. 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...
heiche Posted June 13, 2013 Share Posted June 13, 2013 another guess: maybe try cleaning your throttle body? BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT Link to comment Share on other sites More sharing options...
breadstick Posted June 13, 2013 Author Share Posted June 13, 2013 I haven't had any codes and it seems pretty good at speed, but I haven't had the car long and have nothing to compare it to. I cleaned the maf with and that didn't fix it. Link to comment Share on other sites More sharing options...
Drogos Posted June 14, 2013 Share Posted June 14, 2013 when my bpv hose poped, idle was all over the place Link to comment Share on other sites More sharing options...
breadstick Posted June 14, 2013 Author Share Posted June 14, 2013 How do you clean the throttle body? Link to comment Share on other sites More sharing options...
ScoobyGT15 Posted June 14, 2013 Share Posted June 14, 2013 Throttle Body Cleaner. http://www.autozone.com/autozone/accessories/CRC-Throttle-body-and-air-intake-cleaner/_/N-25uv?itemIdentifier=55922_0_0_ Just have to spray it down really good to let it soak in and then spray it all off and dry with an air gun Link to comment Share on other sites More sharing options...
ScoobyGT15 Posted June 14, 2013 Share Posted June 14, 2013 My car has this problem too. A few times it has felt like it was going to stall out when I came to a stop. I haven't really looked into it yet but I'm planning on it this weekend. It could be a number of things. Most of the guys that already commented have covered what could be wrong though. My friend had a vacuum leak and when he came to a stop if he didnt hold the car at a high idle it would just die. My sister in laws car was running spotty for a week until I cleaned the throttle body and the car was like brand new. Its probably just some simple maintenance that has to be done to the car but try everything that these guys said. Its most likely an easy, cheap and quick fix. I'll let you know what was wrong with mine over the weekend. Link to comment Share on other sites More sharing options...
heiche Posted June 14, 2013 Share Posted June 14, 2013 i haven't done it with the engine in the car, but i believe what you do is pop off the big rubber elbow between the intercooler and throttle body, turn on the key, and have someone press the throttle pedal all the way down (even though it's drive-by-wire, i guess it will respond this way) At that point, you can use some cleaner on a rag (brake cleaner, carb cleaner) and wipe it out, especially in the TB where the blade sits when it's "closed" at idle, as well as the outer edge of the blade itself. sometimes you can get buildup in those places, and it reduces the amount of air that gets by at idle, and that can drop your idle rpm if it is more than the ecu has authority to compensate for. BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT Link to comment Share on other sites More sharing options...
ScoobyGT15 Posted June 14, 2013 Share Posted June 14, 2013 You can also try sea foaming your engine to clean everything out. I haven't tried this yet with our car but I hear the sea foam does a really good job of cleaning everything out. *Warning* your car is going to smoke for a while. But look it up on youtube on how to do it Link to comment Share on other sites More sharing options...
breadstick Posted June 23, 2013 Author Share Posted June 23, 2013 I replaced the O2 sensor, so it's not that. I don't think it's the OCVs or intake manifold gaskets because (from what I'm reading on here) those problems almost always present themselves when the car is cold and mine is when it warms up. I zip tied all the vacuum lines I could find and didn't see any that are off or loose. I guess I'll be trying to clean the throttle body this weekend and spraying all my vacuum lines with starting fluid to double check all my vac lines. Link to comment Share on other sites More sharing options...
breadstick Posted June 24, 2013 Author Share Posted June 24, 2013 Tried the starting fluid on my vac lines today. No difference in RPMs when I sprayed them. I'm hoping I can get to the throttle body cleaning on Wednesday. How hard is it to get the throttle body hose off? I've only had my TMIC off once and I didn't look to see where it connects. A friend has offered to lend me the accessport from his 2013 STI (both use the sub-003 AP) to see if loading the OTS base map will make a difference in the low idle, slow throttle response, and jerky acceleration when floored and boosting. Hoping to do that this weekend. Link to comment Share on other sites More sharing options...
heiche Posted June 24, 2013 Share Posted June 24, 2013 oh it also has slow throttle response and jerky under boost? probably not a dirty throttle body then. have u checked for error codes? BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT Link to comment Share on other sites More sharing options...
breadstick Posted June 24, 2013 Author Share Posted June 24, 2013 I've only had a CEL once after getting a compression test (from turning the engine over with no spark plug in). Link to comment Share on other sites More sharing options...
breadstick Posted June 25, 2013 Author Share Posted June 25, 2013 Will spark plugs cause this? I first noticed this after I got my spark plugs changed (had the mechanic throw them in after the compression test). I have no CEL and I think my gas milage is about good, but my idle is low ONLY after the car warms up and it shimmies a bit at warm idle. Also, I'm pretty sure my throttle response is a bit lacking, but I got the compression test not long after I bought the car so I don't know if it was happening before. I didn't notice it during the test drive but it could have been there. Link to comment Share on other sites More sharing options...
heiche Posted June 25, 2013 Share Posted June 25, 2013 Sure, could be. Always a good idea to think if anything that changed just before the problem started. So if plugs were changed.... Maybe throw in a set of NGK LFR6AIX gapped at .030" and see if that helps. Suppose it's also possible that something got disconnected during the compression test (vac line, etc... although you've checked those over) BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT Link to comment Share on other sites More sharing options...
breadstick Posted June 25, 2013 Author Share Posted June 25, 2013 All the LFR6AIX plugs I can find are the -11, which from all the reading on this site says is for the NA cars, not turbo, and gapped to .44. Are you suggesting to get these plugs and reset the gap to .30? Will that work? Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted June 25, 2013 Moderators Share Posted June 25, 2013 breadstick, do you need a set of plugs? I have 4 in the garage that I'm not going to get around to using for quite some time. Shoot me a PM. BTW, LFR6AIX is not the correct part. You want SILFR6A plugs. "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
heiche Posted June 25, 2013 Share Posted June 25, 2013 breadstick, do you need a set of plugs? I have 4 in the garage that I'm not going to get around to using for quite some time. Shoot me a PM. BTW, LFR6AIX is not the correct part. You want SILFR6A plugs. Yes, I believe there's been a lot of discussion about this around here. The correct part is SILFR6A However, if you gap NGK LFR6AIX at .030" it's virtually the same thing (works fine for me) BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT Link to comment Share on other sites More sharing options...
breadstick Posted June 26, 2013 Author Share Posted June 26, 2013 So, I'm man enough to admit when I do something stupid and it's hard to top this one. I've spent hours reading and researching and troubleshooting and everything to find out it was completely my fault. A car I usually drive has the tick marks for RPMs at every 200, instead of 100 like ours. I saw the 500-1000 marks and thought it was the same. That's right, folks. I was reading the gauge wrong this whole time. I'm an idiot. It reads 750 RPMs at idle just like it should. Thank you all for your help. Link to comment Share on other sites More sharing options...
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