Need Help! 987 Cayman CEL and throttle hesitation
 

Ok, need some input. Car has had the odd throttle hesitation and threw a P0421 code a month ago, which I posted here. Says warm up catalyst efficiency below threshold (bank1). We changed the cats to a much newer oem set (my car has 97,000 kms), new set is about a quarter of that mileage. Drove about 250kms and throttle hesitation is back as well as a new code (pictured below).

Throttle body has been cleaned, cats look new, new header gaskets. What else can it be? I’m thinking MAF or need new O2 sensors. Anyone else seen this?

Car is 2006 Cayman S.
https://uploads.tapatalk-cdn.com/201...0e5a1959fa.jpg


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Ok check the tightness of header bolts.
If there’s a leak there the first lambda will see lean mixture coating the cat with fuel the second lambda will see over rich triggering the Code

Header bolts are fine. Still throwing code.


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Replace bank 1 sensor 2 and that should fix it. If it comes back then your “new” cat is bad.
B1S2 is after cat
Tony

But the reader is saying bank 2. Am I reading your message right?


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Before I changed out ANYTHING, I would read the fuel trims to see where the engine is; it may not be the sensor at all...……...