I believe I've solved the fuel pressure leak down with the new spider assembly, which included a new FPR. Engine starts up immediately now and idles pretty smooth. The LIM is interesting though. I'm wondering if this may be where one of my coolant leaks is coming from. I'm seeing indirectly a leak that looks as if it is starting from up and under front intake under gooseneck, behind water pump, and it's pretty substantial. I took a break from it today, and will check it better tomorrow as well as check cat too.

Lanny, I may take you up on the cat install if this one proves faulty. Thanks guys.

 

The LIM gasket is a gimmie with 15000,0 chevy used junk gaskets they should be ashamed. PURE JUNK. sticker om my 2000 was 34000 though I paid for a good gasket then.

 

Sounds like I'll be going deeper!

 

If you end up replacing the lower intake gasket, use Felpro MS98002T. Do yourself a huge favor before you remove the distributor: Use a socket & ratchet on the crankshaft bolt and manually rotate the crankshaft clockwise until the rotor is aligned with the "6" on the distributor housing. Then, DO NOT move the crankshaft while the distributor is removed. When reinstalling the distributor, make sure the rotor is aligned with the "6" when the distributor is fully seated against the manifold.

 

Will do, thanks for the heads up Cap!

 

Took your advise and removed pre-cat O2 sensor on drivers side and ran engine. It ran great, accelerated as it should, held temp and returned down to smooth idle. Returned O2 sensor and engine bogged when accelerated, an ran bad when stepped up off of idle. I ran this test three times with the same results so it looks as if there is a blockage in exhaust, and I'm assuming the cat. Exhaust is factory, and I see what looks like a resonator or similar coming off of exhaust pipes joint area, then short run to cat, then another pipe to muffler. these are all factory welded together, so what would be the least expensive way to solve this apparent cat blockage problem. Can I just cut out cat and replace with aftermarket, straight pipe, etc, or do I need to replace everything? Once again, appreciate any advice or direction I can take on this.

 

What appears to be a resonator upstream of the catalytic converter, is a "pre-converter". It is replaced as an assembly:

 

You could seek out a used Y pipe from a salvage yard. It should mate up with a oem cat and then on to the muffler. Most have the flange cut off and an aftermarket cat welded on. With some good luck a Y pipe with the flange in tact is out there. I like keeping things stock. Never know when you need to separate the exhaust system and a welded system must be cut to do this.

 

Would the pre-converter also get fouled or clogged like the regular catalytic converter and need replaced, because of raw fuel entering exhaust system? I'm trying to determine if I should just purchase an aftermarket cat and fit/weld/bolt it in place of existing one, or, purchase complete unit like Captain Hook has shown. Cost is a consideration, and it appears to be a several hundred dollar difference.

 

I have 3 Blazers only one has the pre cat. I would seek a salvage yard y pipe with no precat. But that is me.