Both O rings are present for the PCV valve, and I resently replaced the IAC incase that was the cause. This has been going on for several tanks of gas also, so I don't think it'* water in the fuel.

I did notice if I unplug the vacuum line from the Fuel Pressure Regulator on the rail that the tubing smells like gas-- is that right?

No thats not right. If you smell gas at the Regulator vac line your diaphragm is leaking and the Reg needs to be replaced.
Think it was a recall in 98 or 99?

Hmmm so could that be causing a problem?

Also, this weekend my friend and I scanned it with a Tech II

We also did a brake torque to see if the knocking was really happening... it did knock with the brake torque test. It seems like it only misfires at downshifting and other wierd times, not at WOT. It applies KR lightly most of the time, and higher amounts sometimes, its really strange.

Somebody else suggested doing the fuel filter?

Daron

It'* a $10 maintenance item. If you haven't changed it or know when it was changed I'd suggest it. Don't think it'll cure your problem though.

Your fuel regulator needs to be changed. Its drawing fuel into the intake chamber.
This unburnt fuel could explode and cause major damage to the upper.

OK, I'll take care of it right away.

Also, I'd like to replace the fuel filter-- where is it located? Under the car?

Thanks

Passenger side inner frame rail. In front of the rear tire.