Subaru Impreza GC8 & RS Forum & Community banner

1 - 20 of 21 Posts

·
Registered
2017 WRB BRZ w/PP
Joined
·
1,739 Posts
Discussion Starter #7 (Edited)
Well, after drving around at lunch today, it started doing the same thing again. Not CEL yet tho.

scoobaroo said:
post a vid or sound clip plz
I will try, but I dont know if it will do it at idle. I'll give it a shoot tho.

For refernce, I'm running Borla replica's, RT HFC, and Borla catback.
 

·
Registered
2017 WRB BRZ w/PP
Joined
·
1,739 Posts
Discussion Starter #8
ok, one thought I had. The car is still having the hesitation, stumbling, but very intermittent. When i reset the ECU, I only let it idle for about 1 min, could that cause it too behave like this? I drove around for like 20 minutes today with no signs, but then on my way back from autozone, it started doing it again.
Also, have yet to throw a CEL. Please help me out guys, I really want to hit up the autox on sunday, but its 3 hours away and I don't know if I trust my car to make the trip right now. Thanks,

-bob
 

·
Premium Member
overdeveloped beater
Joined
·
8,335 Posts
Go to the autocross. Before you go, reset the ECU again and let it idle up to full temp before driving. Then drive normally to the event....you should be good to go.
 

·
Registered
2017 WRB BRZ w/PP
Joined
·
1,739 Posts
Discussion Starter #11
Storm said:
Go to the autocross. Before you go, reset the ECU again and let it idle up to full temp before driving. Then drive normally to the event....you should be good to go.
Well, I tried this today and as soon as I hit 5th gear driving normally at ~55 mph, it started doing it again. It drive fine the whole time until I hit the highway tho. I'm at a loss as to what the problem could be. How long does it take to throw a CEL? I'm don't know if I should have the stock cat section put back in or order up a new o2 sensor. I hate to say it, but I'm starting to hate my car at this point. :( :( :(
 

·
Premium Member
overdeveloped beater
Joined
·
8,335 Posts
I'm starting to think it's something unrelated to the HFC. Go over everything you had your hands on while under there and check under the hood for something else outta whack.

Too many people have gone with a HFC or no cat and not had any problems.....
 

·
Registered
2017 WRB BRZ w/PP
Joined
·
1,739 Posts
Discussion Starter #13
Storm said:
I'm starting to think it's something unrelated to the HFC. Go over everything you had your hands on while under there and check under the hood for something else outta whack.

Too many people have gone with a HFC or no cat and not had any problems.....
Thats just it. When I had it installed, the only other work I had done was my rear wheeel bearings replaced and the install of my 2pot rears, backing plate style. So the only thing that has changed is the cat section and the rear brakes on the car.

I'm at a loss. I went driving the other night and breifly hit ~65 and no issues, i was like "Sweet" ECU learned the new CAT. Well, I'm driving last night and it started doing it again. And I still have yet to throw a CEL.
 

·
Premium Member
overdeveloped beater
Joined
·
8,335 Posts
Does the CEL come on when you first turn the ignition on? What I mean is, is that bulb burnt out and you have a code that isn't showing?
 

·
Registered
2017 WRB BRZ w/PP
Joined
·
1,739 Posts
Discussion Starter #15
Yeah, the CEL flashes for a second when I first start it. I went for a drive just now, and here is what I witnessed:

note: "it" usually refers to running like @ss

-It starts doing the stumbly/hesitating thing usually around 65. I was driving for prolly a mile or so at 60 and it didn't do it.
-I've found that when it starts doing it, if I floor it, it just gets worse and sounds like it's missing or running really rough until I let off or clutch in.
-If, when it starts doing it, i let off the gas and smoothly get back on it, it stops doing it for a little bit, but usually only for 5-10 seconds.
-So I've concluded that letting off momentarily solves the problem, albeit for brief couple seconds. Could this mean something like a TPS or some other sensor is going bad and has a dead spot?

Keep in mind the car has been doing this for ~100 miles on the trip-o-meter and still no CEL.

I've been thinking about just picking up a new OEM front o2 and throwing it in. Do you think this would be a worthwhile move? At least then if it keeps running like this, I've eliminated the front o2. Would the rear o2 cause the car to run like this?
 

·
Registered
Joined
·
4,360 Posts
Most likely a front O2, as has been said. It's just not bad enough yet to trip a CEL. Anytime you mess around with an old O2, pulling it out of your stock pipe and putting it in the HFC, you run the risk of damaging it, particularly if the car is still warm when you do the swap.

Also give your plugs a look and make sure they're in good shape.
 

·
Registered
2017 WRB BRZ w/PP
Joined
·
1,739 Posts
Discussion Starter #19
Thanks for all the help. I ordered up a new front o2, should be here tomorrow or thursday. Will let you know how it goes. I'll also give the plugs and wires a look-over. Thanks again.

-bob
 

·
Registered
2017 WRB BRZ w/PP
Joined
·
1,739 Posts
Discussion Starter #20
Just as an FYI to everyone, I switched out the front o2 with a new one from subarupartsforyou.com ($74) and she runs like a champ! w00ty h00!

-bob
 
1 - 20 of 21 Posts
Top