I pulled the valves of off #3 and didn't see anything wrong. I'm done with this damn thing. I'm just gonna bolt everything back up and drive it till it dies. It will eventually stop knocking sometime. I've already spent over a grand on it already and countless hours, I'm done. Unless someone can think of something by 9pm tonight, I'm putting it back together.

Put it all back together last night. It doesn't knock anymore when you disconnect the injector but still knocks around 2k rpms.

Can you get video of the knock? Now that it's back together, does it sound like it's coming form the top or bottom of the engine? Have you tried swapping the injector on 3 for one further away like 6 to see if it's a noisy injector?

I've swapped in a completely separate set of injectors with no change. I can try and get a video tomorrow.

I've been reading some more and some people have had issues with their knock sensor causing a knocking like mine, so I ordered one from good ol Rockauto.

O2 sensor, not knock sensor.

Finally, the video: http://i53.photobucket.com/albums/g4...ps630f8469.mp4

The new O2 sensor didn't do anything but make the idle a bit smoother.

I've changed the oil 3 times now and the knock stays the same. I've even added Lucas and STP oil additives and no change in the sound. No clue anymore.

Can you find a source to temporarily swap out the head assembly? If you replaced the whole upper half and it stayed the same, you'd at least be cutting that out. :huh:

I would but the 2.5 head isn't easy to find at the junk yards and I had to ship mine back to the vendor I bought the head from. If someone has a 2.5 head lying around, I'd swap it in. Would only take a couple hours.

I can't pinpoint the exact location of the noise but it is coming from the top end.

What year? I traded my 91 2.5 with enkeivette for legal retainer. Not sure what if anything he's doing with it at the moment. I don't want to volunteer anything for him, but if it's compatible, hit him up, he might not mind if it's just sitting around at this time.

Mine is a 98, I believe the only difference is his is carb'ed and mine is fuel injected. Not are if the head is the same casting though.