I just moved to WA from CA (yeh no smog...in the air or with the truck) and I have the insane CA emissions on my 99 Expy. I read in another thread that someone removed just the front Cats and upgraded the rear ones to Magnaflows. Is this a good recomendation or should I just leave the truck the way it is.

Currently I have a Flowmaster exhaust with 3"'s out the back.

Thanks.

 

Honestly, and this comes from someone who has mucked around with the cats on these trucks, leave it along unless your cats are clogged.

 

Thats the general consensus I've been seeing. Sounds like the Cats stay.

 

I'll see if I can dig up some of my posts on the subject. I just don't feel like typing out the whole ordeal.

 

Remove the cat assembly. Chuck your plumbers snake up in your electric drill. Start drilling away. The snake will pulverize the material. Reinstall the hollow cats. Delete the DTC code for the rear O2s using your tuning software. Cost:$0. Just your time.

 

Don't touch 'em. Seriously. If you remove your cars or hollow all of them out it will rap and sound like garbage.

 

This from a guy with what appears to be a performance vehicle, so much so that it requires a wing to keep it from going ariborne. Please!

 

huh? I'll give you the benefit of the doubt on this one but it is quite obvious that you have never dealt with the exhaust on these trucks...

 

This coming from a guy with 6 posts????????
Cmon, CMK knows what he is talking about, hes a vet with these Expys and the mustang he shows in his sig is just one of his vehicles if you cant read his sig (2000 EB Expedition). If you took the time to read the forums and see what peoples personal "Experience" {yes it is first hand experience} with this issue you will see that CMK is right on the point. Before you start blasting a senior member of these forums new guy, learn some manners and get a clue what you are talking about.

 

Sup guys? Hey, big question...how many miles is everyone typically seeing from the stock factory cats before they are needing replacing? I've got some power issues I think might be related, and am at 154,000 miles currently (saying the 265/70/16 tires have been properly accounted for...otherwise, it may be more!)

 

I replaced ours with somewhere around 85-90k on it. The truck was sucking gas a lot faster than usual and couldn't hardly drag itself up a hill at interstate speeds.

 

Man do I hear that! Feels like an iron pig around here in CO. I can't ever keep speed up hill in ours. I'm thinking it is time. Can I test this theory easily? I know I could with a temp gun...which if I get to drive it to work ever again, I'd have access to one...mostly it is the family rig though, and my wife drives it. I think I'll go do the exhaust blast test on it too...see if there is a change from idle to 3,000 rpm in exhaust pressure.

I think I read somewhere about unplugging a sensor? Which and where?

This morning I'm off to clean my MAF. I don't like how the truck sits at idle and varies between 550 and 800rpm....maybe I'll grab a can of Sea Foam while I'm at it too...always good for a smoke show!

Thanks dude!

Sam

 

You might hook up a vacuum gauge also and get an idea of what's going on at higher RPM. Cheers

Tommy

 

Where at man? What am I looking for?

 

OK, say I wanted to do my part to speed global warming...I know it is against everyone's rules, but could I remove these suckers and go with flanged pipe in its place? Maybe I'd be really nice and throw the empty shells of the cats over said pipe to make it look like they are still in place.

All I need to know is, can I strap the rear O2 to the frame and trick the computer into thinking everything is A-OK? Or will it throw codes. I had a Dakota pickup that ran just fine this way...never know from one make to the next though.

Thanks man! If you don't recommend this...how about cheap replacement parts? Just need 49 state!

Sam