you should only have an o2 sensor if your car has a mass air sensor if it is speed density it should not have one.<br><br>LAter<br>Black_thunder

Well, admittedly i am an amatuer at this stuff, much better at data networking ... however, i think that i messed up when i gave denomms my current exhaust run down.. he has an 88 5.0 and i have a 94 4.6... my description earlier on this site was from memory, manifold to precat to 2-1 precat/resonator to cat to 1-2 y resonator to 2 mufflers ... parked up on curb and took a look...and it seems that after the manifold there is what looks like a cat converter a side (bulbous thing about 10 inch long with tin sheilding) that then runs into a pipe a side that runs into 2-1 resonator/cat (don't know what it is but it is bulbous and has tin sheilding also) to what looks like a small muffler to the 1-2 y (before I had said this is a resonator looking thing also but it is not) to mufflers. On the cat or whatever it is right after the manifold, there is a sensor with a wire running from it, and after that device on the pipe before the 2-1 resonator there is another sensor and wire running from it. So i don't know, seems to me like there are 2 sensors per side...and the car does have a mass air flow sensor... what I was going to do now was leave the 2 sensors a side in the new set up... put a high flow cat between them (ANy suggestions on a good brand?) and then 2 pipes to the back and <br>a pair of offset flowmasters. Call me anal, others do, but have concern of sensor readings before and after high flow cat... may make a check engine light... thanks hnicksta