Tdubya

I replaced my cracked exhaust manifold/cat combo with a direct fit Magnaflow 50602. I reset my codes by disconnecting the battery for 5-10 minutes. How long does the computer take to "relearn" the proper air fuel mixture? I'm guessing that's why it has developed a very slow rough idle as soon as I finished the work.

The car ran fine before the work, even though the cel was on, and I was getting great fuel mileage (about 30mpg).

A while back I tried disconnecting the battery and going straight up to the inspection place to get the car inspected, but it didn't pass because the o2 sensors and cat weren't yet sending the right information. It took a morning and evening commute and a trip to the store before it came back on. I'm guessing this is about how long it should take for this to go away, but I figured I'd throw the question out there. Thanks in advance for replies.

Tdubya

2000 Honda Civic LX 132k miles

About 6 weeks ago I installed a direct fit cat from magniflow. I reset the cel and the code never came back until today P0420. I'm wondering what I should look at first. I'm guessing it's possible that one of the nuts on the head that hold the manifold in place has become loose. I reused the same manifold gasket as it was in perfect shape when I removed it. The 02 sensor isn't loose. Any ideas, or general area to start investigating the cause?

4-5 months ago I replaced the coil, cap & rotor, plugs & wires

ps. the rough idle situation fixed itself after a commute home

Tdubya

wow...guess I need to take my posts elsewhere
thanks