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Discussion Starter · #1 ·
Hey all, new to this forum. As of yesterday my 2012 GT started shaking very bad under acceleration and a bit rough on idle. I recently (in past 2 weeks) got BBK long tube headers and high flow catted X pipe installed. I ran into a few bad connecter problems for the o2 that through some cell codes but seemed to get them fixed. Then I got obdii codes p0420 and p0430. Cats under minimum threshold...But the car ran fine still until yesterday the shaking started after a cruise. New code p2098...bank 2 rear sensor too lean. Cleared all codes and reloaded my Bama tune.

I had no power and with the shake so violent I'm surprised I made it home being 15 miles away. I have no idea what exactly it could be. Engine light remained off even with that much trouble. The only things that I changed were headers, high flow cats, extender connectors and a new tune from American Muscle. I'm guessing it's something with connections, a bad o2...or a bad high flow cat. Does anyone have some ideas? I know misfires can cause this shaking too but I had a misfire before headers due to accel super coil but the cel would come on almost immediately and flash. Help!!!!! :confused:
 

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Discussion Starter · #2 ·
Also the exhaust would sound like it had back pressure I would say or perhaps lack of not sure because it would crackle and pop pretty loud on deceleration
 

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Sounds like the cats could be plugged. I hope not, though. You should talk to the tuner.
 

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Since you're getting a lean code in only one bank and experiencing the hesitation "all of the sudden," it sounds like you have an exhaust leak before the O2 sensor. These late model Mustang 11-14, are all equipped with factory wideband O2 sensors, opposed to narrow bands. If you have any kind of exhaust leak before the O2 sensor, it will drastically throw off your tune. Especially at WOT.

Torque all of the header flange bolts down a second time. It's good to do this after a few heat cycles with new gaskets. Also, check the connection of the driver side header to the Xpipe. Make sure it's snug and not leaking. Look for black soot around the joint to see if it is leaking.

Give this a try and let me know if you have success. If you don't, give me any additional details you may have and we'll go from there!

Shane
 

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Discussion Starter · #5 ·
Thanks for the responses! I wondered that myself Shane, the shop I had install them torqued them down again like 2-3 days after install but it is possible they loosened up a bit. I will definitely check that out when I get a chance to get under there. I am curious though, wouldn't I hear an exhaust leak or wouldn't it do that at all times? It seems to start up kinda bad then after it mellows out runs OK...After distant cruise or a few short WOT punches it gets the studder on acceleration. I did try giving BAMA at American Muscle a car and they weren't too sure without a data log.
 

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Thanks for the responses! I wondered that myself Shane, the shop I had install them torqued them down again like 2-3 days after install but it is possible they loosened up a bit. I will definitely check that out when I get a chance to get under there. I am curious though, wouldn't I hear an exhaust leak or wouldn't it do that at all times? It seems to start up kinda bad then after it mellows out runs OK...After distant cruise or a few short WOT punches it gets the studder on acceleration. I did try giving BAMA at American Muscle a car and they weren't too sure without a data log.
Sometimes if the exhaust leak is very small and in a weird location, it won't make much noise. A friend of mine had an exhaust leak on his 2012 GT500 and we couldn't hear it at all. The car was pretty loud though and the leak was extremely small. However, the car ran terribly. Once we fixed the leak and reset the fuel trims, it ran perfectly!

Regardless, a datalog could be helpful. Take one that replicates your symptoms and send it to the Bama Team. They'll be able to see if there's an air or exhaust leak.

Try tightening up the exhaust again and let me know if that works out for you. I'm very confident your issue lies there!

Shane
 

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Exhaust leaks can be funny too - they can close up when the engine gets warm or open up when the engine gets warm. Seems like a good thing to look at.
 

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Discussion Starter · #8 ·
Thanks again Shane. Gonna get under there tonight or over the weekend. Just to give a little more info on my problem:

I started 'er up after I got home from work. Let the car get to almost operating temperature...reset my odometer and watched the clock time. Car started fine now with no bad idle and all power was there. Went for about a 20 min car ride (8.5 miles or so on back roads) just being easy on it. Running great still. Got on the highway for another 8.5 miles or approximately 10 min I'll say. Still no problems. I get off highway and get back on heading back home....and punch it WOT on the ramp...Like a minute or so later...Shake n Bake time.. and there goes the coyote power. Cyaaaaa. CEL yet to come on during all of this. I'm agreeing with exhaust leak now and I'm actually wondering if by chance my install shop got the oem o2 wire harness crossed so the o2s are reading wrong sides. (Read a post from Ben speed about this causing a similar problem). Once I take a look I'll check that and also tighten everything up again and post if the problem is fixed or not. :)
 

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Thanks again Shane. Gonna get under there tonight or over the weekend. Just to give a little more info on my problem:

I started 'er up after I got home from work. Let the car get to almost operating temperature...reset my odometer and watched the clock time. Car started fine now with no bad idle and all power was there. Went for about a 20 min car ride (8.5 miles or so on back roads) just being easy on it. Running great still. Got on the highway for another 8.5 miles or approximately 10 min I'll say. Still no problems. I get off highway and get back on heading back home....and punch it WOT on the ramp...Like a minute or so later...Shake n Bake time.. and there goes the coyote power. Cyaaaaa. CEL yet to come on during all of this. I'm agreeing with exhaust leak now and I'm actually wondering if by chance my install shop got the oem o2 wire harness crossed so the o2s are reading wrong sides. (Read a post from Ben speed about this causing a similar problem). Once I take a look I'll check that and also tighten everything up again and post if the problem is fixed or not. :)
Glad I could help buddy!

Your story above definitely reflects the symptoms of an exhaust leak. Now we just have to find it! Although the potential issue of crossed o2 sensors could be a real possibility too. That's another good component to check while you're under there.

Hope you're able to find the issue this time around. Keep us posted!

Shane
 

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Discussion Starter · #12 ·
Well that would cause a shake but pretty sure it would cause a misfire AND/or CEL.....Shane one more question, where was your friends leak abouts? I am pretty sure but not positive if it is an actual hole or cracked I'd be able to hear the leak, but then again maybe not....so my question is what if I block off the tail pipes n try to find it (heard this works) but I'm afraid it will cause damage to internals...thoughts?
 

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I Can Indeed.

It's something to check ... What if the "new tune" turned off certain diagnostic monitors?
These cars don't have spark plug wires.:shakehead
 

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You know, I realized that late last night after typing my answer. I'm busted!

:rofl:
Don't be too rough on yourself. I thought that was a good answer. If it has a plug wire near the header, that could be the problem. That means they took his Coyote engine out when he wasn't looking and stuck some old pushrod motor in it.
 

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Discussion Starter · #19 ·
Don't be too rough on yourself. I thought that was a good answer. If it has a plug wire near the header, that could be the problem. That means they took his Coyote engine out when he wasn't looking and stuck some old pushrod motor in it.
Hahaha now that would suck, although the old engines are so much easier to work on.
 

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Discussion Starter · #20 ·
Decipha3326697 said:
what your experiencing is perfectly normal, give bama a call and tell them to send you an updated tune

heres the details

EFIDynoTuning • View topic - X pipe Tune Adjustments Required
That does make logical sense, but however I already had an after cat xpipe installed prior to the headers. I had to change to the matching header brand catted xpipe with a new tune from Bama @ American Muscle.

Also as an update I got the car in the air and tightened all flanges (except headers to engine block, was pressed for time). Checked the o2 harnesses. All seemed good. Still having same problem so I got some live data througb reader and it shows front o2s with bank 1 reading a range of mA and bank 2 reading very little mA both on idle. When driving I get close readings about 3.0 +/- from both o2s on deceleration. I have no idea what readings should be?
 
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