Well this car has been through more than its fair share of o2 sensors and we have to pass an OBD scan emissions style test here in StL.
With 128k on the car we had a solid 0420 for the last 3 - 4 months.
I replaced the front o2 first.
this is probably the 8th or 9th front O2 to go in.
the dealer did 5 of them while it was still under warranty so for some reason it has always eaten o2s.
Next the stock header had developed a crack and so I picked up a slightly used Cobb racing EL header and Cobb high flow cat.
The previous owner said miraculously he never even had a 0420 with this setup.
When I installed the Cobb I figured it was good insurance to install a new rear o2 since it was still the original.
So with 2 brand new Bosch O2s and a fairly fresh Coob header and cat I get a CEL on the way to the emissions place.
We cleared the code at AZ and we able to squeak through the emissions scan.
Next week its back.
I installed the HELP spark plug fouler rear o2 spacer.
After much reading there are a large majority of the owners that this resolves the issue for.
Last night I took it out to fill up with gas and it was empty empty, like bucking as i pulled into the station empty.
Got on the highway after filling up and the CEL light came on.
Stopped by AZ again and 0420 is back.
So I have new header, new cat, both new o2 sensors and the mechanical fix.
car also has new plugs and wires, fresh oil change and is getting a new thermostat and coolant flush this weekend.
Someone else mentioned getting an i-speed reflash, but I wasn't sure if it was necessary with just the Cobb headers, cat, Borla cat back and a Ganzflow CAI.
I've got my inspection sticker that's good for 2 years but I am really disappointed that all the work I have put into resolving this is for not.
One thing that stands out in my mind was way back when we first got the car we tried an amsoil foam racing air filter and it had the stickiest gooiest filter oil Ive ever seen short of my ATV.
A fellow racer told me that the MAF on the 2.5RS was WAAAY too close to the filter to run an oil impregnated filter.
Could oil contamination of the MAF cause it to run rich enough to through a 0420 code?
I've read thread after thread about the dreaded 0420 and there really isn't much GOOD info out there regarding people that have conquered it, other than by the o2 spacer or by a reflash.
With 128k on the car we had a solid 0420 for the last 3 - 4 months.
I replaced the front o2 first.
this is probably the 8th or 9th front O2 to go in.
the dealer did 5 of them while it was still under warranty so for some reason it has always eaten o2s.
Next the stock header had developed a crack and so I picked up a slightly used Cobb racing EL header and Cobb high flow cat.
The previous owner said miraculously he never even had a 0420 with this setup.
When I installed the Cobb I figured it was good insurance to install a new rear o2 since it was still the original.
So with 2 brand new Bosch O2s and a fairly fresh Coob header and cat I get a CEL on the way to the emissions place.
We cleared the code at AZ and we able to squeak through the emissions scan.
Next week its back.
I installed the HELP spark plug fouler rear o2 spacer.
After much reading there are a large majority of the owners that this resolves the issue for.
Last night I took it out to fill up with gas and it was empty empty, like bucking as i pulled into the station empty.
Got on the highway after filling up and the CEL light came on.
Stopped by AZ again and 0420 is back.
So I have new header, new cat, both new o2 sensors and the mechanical fix.
car also has new plugs and wires, fresh oil change and is getting a new thermostat and coolant flush this weekend.
Someone else mentioned getting an i-speed reflash, but I wasn't sure if it was necessary with just the Cobb headers, cat, Borla cat back and a Ganzflow CAI.
I've got my inspection sticker that's good for 2 years but I am really disappointed that all the work I have put into resolving this is for not.
One thing that stands out in my mind was way back when we first got the car we tried an amsoil foam racing air filter and it had the stickiest gooiest filter oil Ive ever seen short of my ATV.
A fellow racer told me that the MAF on the 2.5RS was WAAAY too close to the filter to run an oil impregnated filter.
Could oil contamination of the MAF cause it to run rich enough to through a 0420 code?
I've read thread after thread about the dreaded 0420 and there really isn't much GOOD info out there regarding people that have conquered it, other than by the o2 spacer or by a reflash.
