Quote:
Originally Posted by Nexus313
I have the EXACT, same issues as you. Same codes, same rough idle same symptoms. Replaced O2s. I dont get misfire codes but can feel slight ones. Do you get a vibration through your steering wheel aswell during idle and cruising from your engine running rough?
Here is my to do list:
Clean intake valves (walnut blast)
Replace Air intake to stock oem air box.
Replace cats to catless dps
Secondary cat delete
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yeah i get some vibration in the wheel - engine runs awful
Quote:
Originally Posted by GEOS07335i
I had the p0420 and 430 cat errors. I replaced with catless DP's. The o2 sensors are typically good for 100k it's a common maintenace issue I replaced both my precat O2's I believe they have help regulate your A/F ratios so if I were going to replace the O2's do the precats first when you do your DP's
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yeah i'm trying to discern whether or not i need to do BOTH o2 sensors and remove the dp's - would rather not spend the extra 500$ to replace all 4 o2's
Quote:
Originally Posted by mweisdorfer
I assume you have a tune that fools the DME into thinking that the cats are still in the car, once you go to catless downpipes.
The secondary cats don't throw codes unless they get clogged. You can always do a secondary cat delete and put 1790 vibrant resonators in their place. You'll gain maybe 5 HP doing that.
The pre-cat O2 sensors should be changed around 100-125,000 miles. The post cat o2 maybe 150-175,000 miles. It sounds like you should replace the pre-cats for sure. The post cat O2 sensors just monitor the pre-cat O2 sensors and make sure they are working correctly.
I'd absolutely walnut blast. You should run 20 Gallon formula Techron 2 tanks in a row w/ 93 octane. Maybe do an engine flush and change the oil.
Spark plugs?
Coils ?
PVC valve ?
Catch can ?
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currently i have no tune at all
planning on doing a walnut blast and seeing what happens after that
spark plugs recently replaced
coils are okay
pcv valve replaced
oil catch can installed and okay
never heard of running 20 Gallon formula Techron 2 - i'll have to research that