Soulflyz

Hey guys,

From the title of this Thread you can see the problem.
I took my car to the track and ran great numbers and about to days later my car started to run different.

Now it 2 weeks later and my car is running like crap. Help!

What it is doing

1. At idle it stays at about 900 rpm but it sounds like it revs up then slows down, also i have i air/fuel sensor that use to read around 14.7 and now stays around 15.7 - 16.5.

2. When i go from hyway speeds and take it out if gear the idle hops bad at about 20 - 40 kph and wants to stall.

3. My exhaust sounds like crap has a bad sound to it best way to say is it rattles like a baseball card in the spokes of a bike. also it sounds like its coming from under my passenger seat.

Things i have tryed is few but here is an idea of what i have done
1. Oil change and oil filter
2. Cleaned air filter
3. tryed new fule

I have no warning light also.

Thanks for any ideas you may have...

tREBs

Have you checked your spark plugs? Any coolant in the oil?

Pickles

iTrader: (1)

also remove tb and clean it. oil buildup from pos crankcase pressure can cause butterfly to stick. Invest in a catch can.

Soulflyz

Without looking like a total newbe what the hell is the tb?

Pickles

iTrader: (1)

Sorry, throttlebody. Take it off it's probably caked in oil, making it hard for the butterfly to open and close properly. I can't tell you whats causing the afr readings, but start here, and see what changes.

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Another thing; I just went over your post again.

With respect to the exhaust sound, and this is possibly affecting your afr reading as well; the flex pipe on your dp (downpipe) may have blown. This can happen easily with engine movement such as you would have had at the track.

Soulflyz

i do think its the flex pipe that i blown... what does it take to fix the flex if it is that will look in the morning?

Welding skills or newbe wana do it myself to save money skills?

Pickles

iTrader: (1)

You're best to replace the downpipe. are u running stock header and dp?

Soulflyz

Not she... if i am or not...

bbbevans89

check downpipe for leaks and make sure your 02 sensor isnt going bad

if you have a stock down pipe it like to blow at the flex part a lot mine blew out in the first 30000 miles so i went after market

stonny9

you exhaust sounds like maybe your cat is going bad/ getting clogged. My cat in my aftermarket dp actually blew itself out and I had a rattle/marble sound in the exhaust from the pieces for a few months. If the cat is only partially gone then you might not have a cel/check engine light.

If you have an exhaust leak then you should be able to hear it.

check the car for any dtc's(diagnostic trouble codes). you may have some even if the cel light isnt on. Most auto stores will read them for free. Just right them down and google the codes to see what they are.

Soulflyz

So if is the flex part do i replace that or do have to do the hole header/dp?

Wolf117

When my flex blew out on my hahn downpipe i just got a flex from vibrant and had it welded on. i think it was like 50$ and like 20$ to get it welded on

Soulflyz

That sounds good for my exhaust but now what about my Idol problem? Im thinking a vacuum leak. Someone said to spray wd40 on the hoses and if it revs up that's the hose with a leak?

bbbevans89

idle could be a bad 02 sensor i think if its bad my car was running like **** also check your cold air intake filter

Soulflyz

Yah i think it is an o2 sensor. i checked all my hoses and my filter... all tight.
next step is to replae my o2 sensor any idea on cost and availibility? aslo is it just plug and play or do i have to get it lined to my car some way?

OK im going online to look up the part i think i need, im not sher the name or part number.

It is a little plastic box that has 2 little hoses coming off of it, its located just right of the engine.
one hoses goes under the platic ecotech cover and ataches to the engine itself, the other if i remember ataches to a platic round item that then attaches to my SC and air intake.

Any idea on what this is called or part number? on my lunch break i will take and upload a pic to help narrow this down. thanks.

Kaisoboy

Have you ever changed the fuel filter? Pore idle and your air / fuel ratios maybe your culprit. Sounds like the car is trying to dump fuel and is being starved. Check the fuel filter. Remember, always start with the cheapest fixes and work your way up. if not I would have to agree with others recommendations as well.

NWAE Cobalt

iTrader: (1)

my money is on a bad cat...

Soulflyz

So i took my car to auto value to see if it is throwing any codes.... NOPE!
So i finaly broke and took it into a local tooner shop that has currently done all the work to my car...
With just a quick free look he says its the Flex pipe or the cat...
Going to have to bring it in next friday for a full look and estamet...
Tuner guy just says drive it nice the next couple days...

Thanks for all the input and help. To bad it was not something easy or bolt on that i could do myself...

NWAE Cobalt

iTrader: (1)

replacing a downpipe is a bolt on...you can do it yourself....