[the real shocker]

after putting the ole stang on the dyno yesterday, we FINALLY figured out my problem that i have been having... ( http://www.moddedmustangs.com/forums...n-vt29746.html ) and finally found the culprit!!

as it normally goes for me, i spent over $500 changing parts out or getting system cleaners run and it ended up being something that cannot be fixed... I had 2 significant vacuum leaks and my headers.....

As you can tell by my signature, I installed MAC long tubes headers a couple of months ago. Once it was on the dyno yesterday, my tuner realized that one of my O2 sensors was not even reading anything...

He then proceeds to tell me that a lot of times our cars will run like crap in lower RPM's because when long tubes are installed, our O2 sensors are moved so far down, that by the time the exhaust gets to them, it has cooled off, causing the O2's to read inaccurate. He then showed me that if i just held the RPM's a little higher for about 10 seconds, it heated the exhaust enough to still be hot by the time it got to the O2's, making the car run perfect....

so if some of you decide to do long tubes, take this into consideration if your car starts acting up a little bit!

[04GTAMPA]

In my case, it makes perfect sense. I'll even get the Engine light on every week with the "slow reading" code on left bank 02 sensor. I might just disable them all together.

[orangeRcode]

My car will run like shit for about 20 seconds after I first start it up. If I let it idle for about a minute it is fine. However, if I fire it up and start down the street around 1500 rpms it won't hardly run. It did when the Predator canned tune and with the custom dyno tune I am currently running.

[the real shocker]

Originally Posted by orangeRcode My car will run like shit for about 20 seconds after I first start it up. If I let it idle for about a minute it is fine. However, if I fire it up and start down the street around 1500 rpms it won't hardly run. It did when the Predator canned tune and with the custom dyno tune I am currently running.

thats how mine was doing... acting like a cold natured carbeurated motor until it warmed up some

[ChrisJ]

I dont have any issues with mine...

*knock on wood*

I never get a code for them...The car starts and runs fine no matter what...It never sputters or anything...

I run BBK Longtubes which should not matter...My tune is done by Tim @ Modular Powerhouse...

I will ask him about it as well...

I mean I dont ever drive my car until it warms up so I dont know how it drives while it is dead cold...

[lil2v4.6]

The guy that did my tune said he had to compensate for the headers by adding a 15% reading code when he did the tune. He said this is because the o2 sensor is farther from the heads than it was before. I will check with him and find out more if you would like me to. All I can say is my car ran like shit before I took it to him.

[ChrisJ]

I remember Tim talking about having to keep the 02 sensors from going into Open Loop or Closed Loop for so long to keep this from going on...I cant remember which one though...