I've posted before about this somewhat before. After driving the car a little more I have narrowed it down to when the problem occurs.

When the motor is warmed up is misses and bogs. This happens especially at 2000 rpms and/or when under 3/4 to WOT. The car shudders and shakes violently, with some backfiring. At 70 mph on the highway it drives pretty nice, until a lot of throttle is given. This doesn't seem to happen when the car is cold.

Other info:
This happened after the header install. The plugs are new (TR55) and so are the wires.
-New fuel filter, Mobil 1, Seafoam, Bar's Leaks
-Has a small timing gasket leak
-Small exhaust leak on I-pipe
-Found a header bolt missing, the primary next to it was white hot. Also the plug closest to it was fouled with oil. Looks like a small head gasket leak.

With the symptoms does this sound like an Opti issue? I picked up a new one and a coil. Time is an issue for me, so that's the purpose of this post. If there is something easier or more probable to check or clean I would rather do that first. I realize I still have to fix the leaks and whatnot. I'm just to busy with finals and wondering if there is anything else to do first.

Thanks

 

Mine did that after headers install. Turned out to be a wire arching onto the header. Ziptied it and problem went away. Definitely check that.

 

I had that problem with an arcing wire. Replaced the plug and wire and it still didn't go away

 

Anyone else?

 

Could this be related in any way to the egr or air removal? Or possible the O2 sensors went bad after we swapped them?

 

Does anyone use the heat jackets on their plug wires after header installs?

 

I used whatever ones were still left on the car. The wires were brand new stockers with less than 2k miles and they were fine. Accept the one wire that had to be routed OVC because it was touching a header