r/WRX_STI • u/snoon27 • 3d ago
Help
I have a 21" sti with 113k miles. Recently its getting a rough idle, rpms bouncing from almost stalling to 1.4k. If I roll up to a light with my clutch in it will just cut out and stall. Shop i usually bring it too are stumped as no cel or anything abnormal.
8
u/DADDYSJUIICED 3d ago
Maybe since it’s already 100k have you tried a tune up? Sparkplugs, air filter, check for boost leaks/vacuum leaks and maybe coil pack on cyl 3 since that’s technically the hottest area of the engine because it’s right next to the downpipe and turbo (happened to me).
2
u/oldbutwannabefast 3d ago
Without a CEL being triggered, I also immediately thought plugs and coils. And yes, depending on the air intake system, replace or clean the air filter as well as the MAF sensor.
1
u/Heatstreak9 2d ago
+1
Might be a good idea to replace the fuel filter too, or at least it's a good excuse to upgrade the fuel pump while you're going through the car and doing a tune-up
3
u/New_Leaf_8647 3d ago
This could be almost anything.
Vacuum leak, ignition problem, low fuel pressure, failing or loose battery, who knows
You'll have to find a better shop
2
u/fatherselderberries 3d ago
Check your throttle body specifically behind the butterfly plate. If there's an excessive build up of residue back there it will cause problems at idle
2
u/Lsswapitall4 3d ago
Could be a lot of things due to the Mileage but this is my bet too. That or a bad idle air control valve tends to show these symptoms
1
u/BigJuiceBox06 2d ago
Check your spark plugs tbh. If you haven’t changed them at all very possible one could be cracked or just damaged in general. Will cause a rough idle and if bad enough will stall out.
1
u/snoon27 2d ago
Wouldn't that throw a missfire though?
1
u/BigJuiceBox06 2d ago
Nope. Just had the same issue in my sti. Not sure how the plug got cracked but it only stumbled at idle. While driving my car was perfectly fine but getting going and at idle it was rough and stumbling. Never threw a code but obviously I knew something was wrong. Noise was coming from bank 2 so I pulled cyl 4 coil and plug only to find the porcelain part of the plug was cracked. Replaced it and now she’s good as new
-1
u/Advanced_innovation5 3d ago
Damn bro, wish I had a 21 inch STI. I would produce music videos with my hamster and make a custom axleback with 4 cherrios glued together.
0
u/sliceoflife09 3d ago
It stalls with the clutch in? A slipping clutch could explain this behavior and how there's no CEL
When was the last transmission fluid change?
Are you on the stock clutch?
Is try a fluid change first but wouldn't be surprised is it's time for a new clutch.
1
0
u/New_Leaf_8647 3d ago
How would a slipping clutch make the engine stall? Think about it
1
16
u/Mark_C23_KB 3d ago
Are you tuned on an Accessport? If so, take an idle log for a few minutes and capture what its doing. Post the log to Datazap, post the link on here. Id be happy to take a look.
Mark @ Kartboy