ORIGINAL: joemilli

Thanks to everybody that posted...I'm gonna check the plugs out today. i gapped them before i put them in so i dont think gapping is the issue, but ill recheck them anyway, better 2 b safe then sorr, right? And yes the car sounds good when I rev it in neutral, the problem is only when the car is under load. How would I check to see if one or more ofthe coil packs has gone bad?? Also what's a good way to test the plug wires to see if those are functioning properly?? I occasionaly run 91 octane could this actually hurt performance?? If so I'll go back to 87 w/ no complaints..

and last but not least the mil debate. I have seen a debate over this. Will the downstream (back) O2 sensors being unplugged hurt the performance of my car in any way?? I have an off-road (no cats) Mac prochamber, no Mils. I heard mils crap out and I'm just saving my cash for a tuner. alotta people sayit does others say it doen't can I get a finalanswer on this PLEASE!!!

Anywaysi want to say thanks again for the help, i really appreciate it guys.

on a side note: don't post if you dont know what the hell your talking about, it does no good to anyone if you give out wrong or incorrect info to someone,, it's frustrating and just waste everybodies time..= ) thanks again everyone...

ORIGINAL: contentsunderpressur

The downstream o2 sensors do NOTaffect drivability. Theylet you know when you have a converter fail. The way to prove it is the MIL eliminators. When you take your converters off the o2 sensors know and throw a code because that's what they are supposed to do. Think about it, the exhaust flows through the first two sensors without going through converters and doesn't throw any codes. Also the converters burn off all the unburt fuel in the exhaust before it gets to the rear o2 sensors so how could they give the computer a true A/F reading? You car could be running rich but the computer wouldn't think so because the extra fuel in the exhaust would be burt from the converters. The last bit of proof is the way the MIL eliminators work. The check engine light comes on because of the reading the downstream sensors send to the computer. The MIL's send one certain reading to the computer all the time just to keep the light off. That is all they do. One of my o2 sensors got broke off when I hit something in the road a while back. I just left the MIL plugged in and tie straped it up. I never replaced the o2 sensor and haven't had any drivability problems.