1sicls1

i just bought this 2003 cobra with 50k miles on it. it looks simi stock i can see the fuel injectors are blue which could mean they are after market but im not sure. i have never owned a ford befor. its got a CAI and Basani exhaust. the car runs good but the service engine light came on. i hooked it up to a diagnostic tool and it spit out 2 codes. it said something about rear exhaust 02 sensors are bad bank 1 and bank 2. when i coast the car on the freeway and or anywhere almost its idel will bog from 1000rpms to 500rpms and it will flucuate up and down when out or gear or in idel. last night i mashed the car up to 100mph on a backroad and when i took it out of gear to slow down the car bogged out and turned off and i had to turn it back on while rolling down the road. can this problem be related to my O2 sensors going bad? the car does smell like it rusn alittle rich. how much are the 02 sensors and can i install them myself. again i have never owned a ford until this week and id like for my new ford family to help me with solving this mistery so i dont have to take it into a dealership. thanks guys

PWORLDSTANG

Welcome to the forum!

You're having a lot of things going on at once with your car. It's hard to say what it could be. Sounds like you may have the stall problem. There is a TSB on it, and a dealer will be able to take care of that for you.

But as far as your CEL light goes, I have no clue as to what that could be. Someone here might be able to help you.

But since you are new to your Cobra,you should join svtperformance.com. There is a lot more information available on our cars over there than here.There'sA LOT of things youneedto learn about your car, and svtperformance.com is a good place to start.Also, If no one here can chime in and help you out better than I can, If you post this in the engine/tuning section (after you search), you'll for sure find the solution to your problems.

PWORLDSTANG

BTW, the blue injectors are the stock ones.

TeddyKGB

Any chance the car has an aftermarket mid-pipe without catalytic converters (aka off-road pipe)?

1sicls1

im not sure about the off road h pipe. i got this read out from autozone.

Here are the codes the PCM spit out
P0420(Bank 1) and P0430 (Bank 2)

TROUBLESHOOTING P0420

The PCM has determined that the catalyst system efficiency for bank 1 is below threshold for the current engine operating conditions. (Bank 1 identifies the location of cylinder #1, while bank 2 identifies the cylinders on the opposite bank)

Definition
Catalyst efficiency low-bank 1
Explanation
The oxygen sensors monitor the catalytic converters ability to store oxygen.

Probable Causes:

1.-catalytic converter defective (failure possibly due to #2, 3, or 4)
2.-Engine misfire or running condition
3.-Large vacuum leak
4.-Engine oil leakage into exhaust-valve guide seals, piston rings


I wish i knew what exactly was wrong with it. i baot some seafoam fuel system cleaner to help clean stuff up in the motor. i gotta take this car back to san fran from chicago. i hope it can make it. sow hat do you guys think it could be or i should do. im scared of taking it to some random mechanic because in my expierence with muscle cars i get f*cked everytime and right now with all my legal stuff i cant afford to many extra costs. my DD has a flat tire so im stuff driving the cobra which is killing me since i gotta drive it 60 miles a day.

TeddyKGB

Try here, there are 45 threads with the 420 code in it.

http://www.svtperformance.com/forums...archid=2012478

specifically this might be a good one.

http://www.svtperformance.com/forums...ighlight=P0420

1sicls1

ill research it. thanks for your guys help in this matter.

1sicls1

do you guys think this issue could be the reason my cobra is getting worse gas mileage then expected lol i gotta take it back to CA from chicago can i drive it with bad 02 sensors? or is that a bad idea???

97blackcobra

02 sensors are easy to replace and they are about $60. All you gotta do is look at your exhaust and you will see it sticking out of the pipe ( kind of looks like a spark plug sticking out of the exhaust pipe). you get the right sized wrench unscrew the old one unplug it then plug up the new one and screw it in. Very easy job todo I did mine my self when i was 16 so..... a bad 02 sensor can very well cause bad gas mileage but i dont know if that is your stalling prob.

mills281e

Could you be running rich? Did the previous owner have the car tuned correct?