|
|
|
|
Thread Tools | Display Modes |
02-18-2018, 01:14 PM | #1 |
Scooby Newbie
Member#: 428916
Join Date: Aug 2015
Location: Orlando, FL
Vehicle:2012 WRX WRB |
Engine struggles to find idle after acceleration
Year/Model: 2007 STi
Mileage: 130k Issue: Car can't find idle So I have been having issues with my car hunting for an idle, it got progressively worse and now it will stall after releasing the throttle if revs go over 3k. If i rev under 3k (say 2500rpm) the rpm's drop all the way down to zero, the car acts like it's going to stall (engine oil light, check engine light, abs, etc. all come on if it had stalled) and then it catches and shoots back up to over 1000rpm only to drop back down to below 100rpm and then it just oscillates back and forth until eventually it either stalls or the idle smooths back out. The car idles fine when first turned on but as soon as the throttle is touched it starts the cycle. I have cleaned and serviced the throttle body, replaced the MAF sensor ( car runs perfectly with it unplugged i.e. limp mode) and yesterday I replaced the fuel pump. The car never drops below 100rpm now but the idle still oscillates after hitting the throttle. I tried to drive it down the street to see how it did and within 100 yards I got a misfire in cylinder 1 ( later the misfire was in cylinder 4) Anybody have any ideas? The car isn't throwing any codes at an idle except P2431 & P2433 (which its had for over two years and only pertain to the secondary air pump). My next step is to replace the idle positioning sensor, which is conveniently integrated into the throttle body so if anybody has any other ideas before I source a new throttle body, please let me know.
* Registered users of the site do not see these ads.
|
02-18-2018, 11:49 PM | #2 |
Scooby Newbie
Member#: 481300
Join Date: Jan 2018
Chapter/Region:
International
Location: Michigan
Vehicle:2004 Impreza WRX STi Java Black Pearl |
I'm having the same issue kinda, My car does idle but it's rough, it does sometimes catch a good idle but again will revert to the though idle with misfires that are audible. I'm currently checking the timing to make sure it didn't skip, Next step would be cleaning the MAF and doing a cylinder compression test, if I come across a fix i'll tell ya to see if it helps.
|
02-19-2018, 09:18 AM | #3 | |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
Quote:
Have you looked for vacuum leaks? Have you cleaned your IACV? Have you checked your Purge Control Valve to see if it is cracked? |
|
02-19-2018, 07:05 PM | #4 | |
Scooby Newbie
Member#: 428916
Join Date: Aug 2015
Location: Orlando, FL
Vehicle:2012 WRX WRB |
Quote:
Will have to check on the vacuum leak and purge control valve though, not entirely sure where it's at |
|
02-20-2018, 09:33 AM | #5 | |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
Quote:
You made me look ... Looks like the IACVs are on the 1990 - 2006 models. Couldn't find one listed for 2007 Hmm ... Looks like you may not have one of these either - VALVE-PRESSURE CONTROL - what I was calling the Purge Control Valve Last edited by Samurai Jack; 02-20-2018 at 09:43 AM. |
|
02-22-2018, 09:15 PM | #6 | |
Scooby Newbie
Member#: 453236
Join Date: Aug 2016
|
Quote:
Swapping out the spark plugs seemed to improve things for me about 1 year ago. But actually today the missfiring got quite bad on the highway whenever I pressed the accelerator more than gingerly. So I ended up taking it in to a professional as i was out of town and away from my tools. My first thought was that it is the fuel pump failing... but i am surprised that you are still experiencing the missfires after replacing yours... I will stay tuned to see what the solution ends up being. |
|
02-22-2018, 09:20 PM | #7 | |
Scooby Specialist
Member#: 298403
Join Date: Oct 2011
Chapter/Region:
W. Canada
Vehicle:2008 WRX Premium Spark Silver |
Quote:
|
|
02-23-2018, 03:59 PM | #8 | |
Scooby Newbie
Member#: 481300
Join Date: Jan 2018
Chapter/Region:
International
Location: Michigan
Vehicle:2004 Impreza WRX STi Java Black Pearl |
Quote:
|
|
02-24-2018, 10:57 AM | #9 |
Scooby Newbie
Member#: 428916
Join Date: Aug 2015
Location: Orlando, FL
Vehicle:2012 WRX WRB |
Did some research and saw more than a few people claiming their throttle positioning sensor was giving them issues. Ordered a new throttle body today, will update if it was indeed the throttle positioning sensor.
|
02-25-2018, 06:39 PM | #10 |
Scooby Newbie
Member#: 453236
Join Date: Aug 2016
|
My similar issue turned out to be a dirty throttle body and a loose coil pack. Cleaning the TB and tightening the coilpack along with resetting the ECU solved my issue. But i see you already tried cleaning your TB.
Last edited by pouncingmailbox; 02-25-2018 at 06:46 PM. |
03-16-2018, 04:42 PM | #11 |
Scooby Newbie
Member#: 428916
Join Date: Aug 2015
Location: Orlando, FL
Vehicle:2012 WRX WRB |
New throttle body and changed fouled cylinder 4 plug and it runs like new
|
Thread Tools | |
Display Modes | |
|
|