HELP O2 sensor or bad cat

[Lukeg3]

Hey guys,

New to the board- been lurking a long time. I'm having a problem that is definitely hard to diagnose, as I'm not a mechanic I figure I would start here and maybe someone can lend a hand.

First off, gen 3 viper with stock exhaust setup having some major problems.

Car racing mint until 3 weeks ago. I started noticing a few things, and being new to vipers I'm not sure what's normal.

I noticed when letting the car warm up, the passenger exhaust wouldnt kick anything out for a good 4-5 mins. Didn't think anything of it, until about a week later when we were throwing a CEL. Code showed that 02 sensor voltage was off (I know nothing about emissions).

Next morning, code went off and stayed off for a few days. Car ran perfectly, then one day at highway speeds came into a hard rain out of nowhere- CEL returned the second the car got wet (maybe a cooincedence)

Then real issues started 2 weeks ago. Car would heavily sputter in and out of power in gears 1-4. Power from the motor felt like it was cutting out, on throttle and as soon as I gave it a touch more gas then would kick in HARD. Felt really dangerous.

After about 15 mins of putting around town hoping it would go away, it did. Then ran perfect for the rest of the trip.

Next day, let the car warm up far longer, and problem occured for the first 15 mins driving again. This car is feeling a LOT less powerful- so I'm not going to drive it until I can get the problem diagnosed.

I've read about clogged cats being common in gen 3's could this possibly be the first place to look?

I messaged my shop to order new o2 sensors and price out stock cats (high flow isn't in my budget atm) I was just wanting your advice before they take the snake for what could be a long period of time to asses the issue. I just want to point them in a possible direction to avoid wasting my time and theirs.

Any advice is greatly appreciated!

Thanks in advance

[daveg]

If you are getting low exhaust output on one side (compared to the other), cat could definitely be clogged. Check to see if that cat is getting abnormally hot as well. I would also put a computer on the port to see if your front and rear O2's are switching.

[plumcrazy]

dont drive a car with a clogged cat. trust me, this is expensive

[Fatman2006]

This might help...Good luck.

https://driveviper.com/forums/thread...onverter-Broke

If it is a clogged cat, it's an easy and relatively inexpensive fix. Not including the SCT device (which isn't required), it was $600. I removed the entire exhaust from the manifold back and then took it to a local exhaust shop to weld on new mufflers. The SCT device, though not required, is certainly a good measure for doing things properly.

[Lukeg3]

This is incredible. Definitely saves me getting new cats/all sensors. Thanks a million. Is it pretty straight forward? If I mention this thread to the muffler shop I'm sure they'll be able to figure it out yeah?

[Fatman2006]

Super straight-forward. Honestly, if I knew it would be as easy as it was, I would have bought a welder and made the exhaust myself. Good luck, let us know how it turns out.

[Blue96GTS]

https://driveviper.com/forums/thread...eady-questions

Had a similar problem recently, only my cats weren't blocked - they decomposed and blew out in pieces behind the car.

The problem you describe sounds all to familiar in my research of my issues, and discussions with other owners. Agree with the other posts that it's likely just your cats.

Some would admonish me for not using the stock cat, but I went with Kooks Hi-Flow Greencats. Time will tell if I made the right decision.

Cats - $369/cat at large (top of the mountain) parts store
Asking a capable friend to TIG weld the cats to the pipes cost me a large bottle of Stranahan's Colorado Whiskey and 12 pack of Fat Tire sampler
A couple of hours of my time removing, measuring, test-fitting and reinstalling everything.

Good luck!

[BlknBlu]

Put a GEN IV exhaust on the car to eliminate some cabin heat.

Bruce