Had these pop up after dealer replaced my cat converter:

P0030
P0053
P0102
P0443

It was running great for about 20 miles then just started running like ****. Any ideas? I thought maybe the dealer erased my hp stage 2 tune and put the stock one back on, but it still revs out to 7k.

 

Can the car even run with stage 2 injectors and a stock tune?

 

why would they flash ur ECU if they were changing a cat?

 

It would run like ass with bigger injectors on the stock tune

 

The idle bounces up and down. It also bucks when I let the clutch out.

 

10 amp "exh" fuse under the hood was blown. I bet when the O2 was rubbing on the frame it blew the fuse. Let's see if this fixes it.

 

I thought you said only ricers run not cats?

 

Completely unnecessary on a street-driven vehicle.

 

So I'm guessing the O2/MAF/EVAP are all powered by the same fuse. Doh

 

Didn't you also say there's no power gain from removing the cats?

 

You'll lose power without supporting mods (gutted cat). Bolt ons are not one of those mods.

A catless downpipe will give you less than 5whp. I think you'll gain about 2.

 

What about spool then?

 

Not sure, never owned a turbo car.

 

How would you lose power?

 

Hot Rod Magazine did the test. Read it

 

Link?

 

Still waiting on that logic-defying article.

 

Does Washington not have access to Google?

https://www.google.com/webhp?sourcei...%20dyno%20test

Just use a high flow cat if you need MAX POWAR from your Chevy Cobalt, which from your sig looks like you've already done.

 

Nope we don't have Google in Washington.

Nowhere in there says catted makes as much power, it says quite the opposite. You're full of ****.

 

...

 

You are not very smart:

Dyno testing has proved that to be true. Mike Osucha says: "We
recently built a 396-cubic-inch LT1 engine that produced 455
horsepower with an open exhaust system. When we installed two
high-flow converters, the engine produced 458 horsepower.

 

run catless, problem solved.

 

No, I used to be catless and it made the car sound and smell like ****. I tried resonators in place of the cat, different catbacks... thousands of dollars using different setups. The best is stock with a ported manifold. When you get into headwork and other major mods then it makes sense to open up the exhaust. On stock heads/intake manifold/sc/turbo it's a waste, just makes you sound like a ricer in traffic all for about 10whp.

 

Well there's your problem. Grab a ported head and run catless!

 

i run e85 so my car smells like corn at idle anyways