Checking the flex plate is pretty easy. Lots of write ups here on it. Can't hurt to look at it.


143k is nothing on these engines. Many of us are well past the 250k on the original chain. Mind you, that doesn't mean yours is good, but I would not change it just because it's 143k.

Yes, it does, but you shouldn't be smelling gas. If your cat is plugged or you have a vacuum leak, or an O2 sensor problem, you'll get a lot of those symptoms.

 

Some updates.

Flex plate is okay. I'm not hearing anything from the timing chain via long screwdriver, so I'm dropping that for now.

Gas smell is likely the exhaust system because the entire thing from the manifold to the muffler looks like rusty, grime-encrusted ****. I would not be surprised to find a crack somewhere in there either. Woops.

Looks like it's back to the drawing board on pinpointing where the engine noise is from.

So let's re-evaluate. Maybe this will help.

https://drive.google.com/file/d/0ByA...hsdTB5OTA/view

This was after driving for a while. Lifters? God forbid if it's a rod knock or piston slap. I can't tell.



While unrelated to the engine, this also happened:



Closed my door last week at work and heard a loud KACHUNK.
Checked it out and the old check hinge pin finally snapped and I can't seem to get the check arm to come back out. Tackling that tomorrow when there's some light and I have rest. Shew.

 

A mechanic's stethoscope is a thing of wonder and great usefulness.

 

Piston slap might be more pronounced cold before the pistons warm up and expand some. My experience with rods is a bad one hammering harder with throttle, with load like climbing a grade. I wouldn't rule out lifters there. I have one 90 with about double your mileage with a stubborn knock I thought was a rod. If it were a rod though it wouldn't have done it for nearly 100K without blowing. I'm wondering if anyone has found their thrust bearing on the crank clearanced. That might be something that could be fairly loud for a long time without "going" (blowing the engine)

A solvent like BK-44 might help a sticky lifter......Crusier has used something he thought helped.

 

This is for anyone who happens to stumble across this thread in a google/forum search.

Knocking noise continues, but has gotten better after switching to Rotella T6 5w-40 diesel oil.

Gasoline smell has disappeared! After replacing the upstream/pre-cat O2 sensor, it went away after a while. Used NTK part #23151.

Slow acceleration; make sure your tires are filled to the correct pressure. Mine were at 25 psi, and needed to be at 40 psi.

The whirring noise: Turns out it was the alternator bearings starting to go bad. Replaced.

Loud rumbling when idle: Several issues. One, make sure the driveshaft and transfer case aren't sitting high up/at an awkward angle. Lower the crossmember either by using spacers or washers. Two, clean your throttle body and Idle Air Control sensor. Three, get a new muffler!

Lots more I have learned than this the past months since I started this thread, but for now, I leave it to silence so that someone else may read this if they have the same problem.

 

Thanks for the follow up!

 

Thanks- I didn't know we could lower the cross member like that. Good tip.