Okay here's the deal:
Last night a few of my buddies and I got together to install my summit racing cat-back exhaust. So we unbolt, cut, and remove the stock cat-back. We then start the stang w/o the mufflers and only w/ the headers and h-pipe on. It sounded so good that we rewarded ourselves by taking a late night trip in the mufflerless stang to Applebee’s to get some food. The car drove great; it was loud, reved freer, sounded like a mustang should and felt like butter. So after we come back out, I get into my car and start her up. The car starts and the tach keeps oscillating between 400 RPMs and 700 RPMS at idle. As soon as I try to give it a little gas, the car wants to stall and die on me. If I give it a lot of gas the car hesitates and drops to 400 RPM and then climbs up to where ever it should be.
By this point, I was pretty sure that it was the O2 sensor sending the computer wacked readings because of the much better/faster exhaust flow through the cats. So I let the engine idle for 5 min to let the computer adjust to the new settings. Still stalled. I restarted my baby and let it idle for 3 min. Same problem. Then I pulled the positive battery cable and let it sit for a while and restarted it and let it idle for a little. Still ran like s**t.
After I did all that I limped my stang home. under acceleration, she would sometimes cut the engine out momentarily at about 3500 RPM or so. The exhaust smelled like the mixture was running rich. And needless to say the check engine light was on. I also made sure the O2 sensors were plugged in tightly.
So, is it an O2 sensor problem? If it is, then why wouldn't the computer adjust to the new settings or worst case go into the closed loop mode or "safe" mode? What can I do at this point? I need some welding work done a my exhaust shop, so it might be a couple days before I can do that and I'd like to be able to drive my stang w/o mufflers until then...and it's really bothering me that it's not running well like this.
Thanks for your help in advance!
Last night a few of my buddies and I got together to install my summit racing cat-back exhaust. So we unbolt, cut, and remove the stock cat-back. We then start the stang w/o the mufflers and only w/ the headers and h-pipe on. It sounded so good that we rewarded ourselves by taking a late night trip in the mufflerless stang to Applebee’s to get some food. The car drove great; it was loud, reved freer, sounded like a mustang should and felt like butter. So after we come back out, I get into my car and start her up. The car starts and the tach keeps oscillating between 400 RPMs and 700 RPMS at idle. As soon as I try to give it a little gas, the car wants to stall and die on me. If I give it a lot of gas the car hesitates and drops to 400 RPM and then climbs up to where ever it should be.
By this point, I was pretty sure that it was the O2 sensor sending the computer wacked readings because of the much better/faster exhaust flow through the cats. So I let the engine idle for 5 min to let the computer adjust to the new settings. Still stalled. I restarted my baby and let it idle for 3 min. Same problem. Then I pulled the positive battery cable and let it sit for a while and restarted it and let it idle for a little. Still ran like s**t.
After I did all that I limped my stang home. under acceleration, she would sometimes cut the engine out momentarily at about 3500 RPM or so. The exhaust smelled like the mixture was running rich. And needless to say the check engine light was on. I also made sure the O2 sensors were plugged in tightly.
So, is it an O2 sensor problem? If it is, then why wouldn't the computer adjust to the new settings or worst case go into the closed loop mode or "safe" mode? What can I do at this point? I need some welding work done a my exhaust shop, so it might be a couple days before I can do that and I'd like to be able to drive my stang w/o mufflers until then...and it's really bothering me that it's not running well like this.
Thanks for your help in advance!
