I Have a 2015 WRX that I bought Pre-Certified with 16K miles. I plan on doing some upgrading but I need to figure out this problem first.
The car stars fine, warms up fine, but when it settles down into a resting idle (700RPM) it seems a little rough. I'm using 93 Octane.
Every second or so, but not regularly spaced out, the engine gives a little "bump". With the hood open you can see the engine move a little when it happens.
Under normal driving conditions the car is fine, no misses, backfires or knocks. I will add though that it has tried to stall on me about 3 times.
Once when I was doing some long steady driving. I had it on cruise control doing around 65 in 5th most of the time, no heavy pulls or turbo use.
Came to a few stops here and there, but at one light the rpm's starting dipping out and the ECM would compensate and bring it back up, repeat. It did it again later the same night.
No CEL, the water temp was fine, no knocks, no smoke, nothing unusual but the idle. The other time was a few days later under normal "city" driving conditions. Tried stalling again, but was fine except for the idle.
It's still under warranty so I had it looked at by the dealership, and they couldn't find a problem.
The only thing i've done to this car has been replacing the most of the intake and charge clamps. This is a pretty simple thing, and the idle was the same before and after.
And yes, because I know it will be suggested, I can go back and check the clamps. No big deal, but im pretty sure I installed them right. And I also inspected the intake ducting for cracks or holes, its fine.
The MAF and neutral switch had to be replaced a few days after I bought the car, but the switch seems to be a somewhat common issue, and the I think (im not sure) the previous owner used an oiled air filter and messed up the MAF. But I'm not sure. Both of these problems occurred simultaneously.
At this point I'm thinking it could be a few things.
1. Fouled spark plugs. Not looking forward to checking these.
2. Bad Ignition coil. Though I think this would throw a CEL.
3. Vacuum line problems. I want to know which ones are directly responsible for idle and inspect them. Maybe there's oil from the turbo in them, just enough to choke them?
I'm open to suggestions and thoughts. I'll try to provide any info needed to help you help me. Thanks!
The car stars fine, warms up fine, but when it settles down into a resting idle (700RPM) it seems a little rough. I'm using 93 Octane.
Every second or so, but not regularly spaced out, the engine gives a little "bump". With the hood open you can see the engine move a little when it happens.
Under normal driving conditions the car is fine, no misses, backfires or knocks. I will add though that it has tried to stall on me about 3 times.
Once when I was doing some long steady driving. I had it on cruise control doing around 65 in 5th most of the time, no heavy pulls or turbo use.
Came to a few stops here and there, but at one light the rpm's starting dipping out and the ECM would compensate and bring it back up, repeat. It did it again later the same night.
No CEL, the water temp was fine, no knocks, no smoke, nothing unusual but the idle. The other time was a few days later under normal "city" driving conditions. Tried stalling again, but was fine except for the idle.
It's still under warranty so I had it looked at by the dealership, and they couldn't find a problem.
The only thing i've done to this car has been replacing the most of the intake and charge clamps. This is a pretty simple thing, and the idle was the same before and after.
And yes, because I know it will be suggested, I can go back and check the clamps. No big deal, but im pretty sure I installed them right. And I also inspected the intake ducting for cracks or holes, its fine.
The MAF and neutral switch had to be replaced a few days after I bought the car, but the switch seems to be a somewhat common issue, and the I think (im not sure) the previous owner used an oiled air filter and messed up the MAF. But I'm not sure. Both of these problems occurred simultaneously.
At this point I'm thinking it could be a few things.
1. Fouled spark plugs. Not looking forward to checking these.
2. Bad Ignition coil. Though I think this would throw a CEL.
3. Vacuum line problems. I want to know which ones are directly responsible for idle and inspect them. Maybe there's oil from the turbo in them, just enough to choke them?
I'm open to suggestions and thoughts. I'll try to provide any info needed to help you help me. Thanks!
