Just had Crawford hi-flow cats installed on my '04 5AT sedan, and am getting a 'service engine soon' (aka CEL) light and it feels like the car has been way de-tuned (VERY sluggish from ~2000-3000 rpm, and sluggish above that too). I suspect the timing is being dialed back by the ECU for whatever reason, but that's just a guess. AFAIK, these cats are supposed to be OK on 2004's....

Spoke to Doug @ Crawford briefly - he's great - and he mentioned there was one customer with an '04 that was leaning out for a couple of days until the ECU adjusted. I'm resetting the ECU overnight (via battery terminal disconnect).

Anyways - if anyone has had similar issues, or can verify they *haven't* had issues on an '04 with these cats, or has suggestions....all info appreciated. Thanks

 

Hey how did this work out? I just installed the plenum and was thinking about the cats next. Thanks

 

hey - it's not resolved yet. hard to say exactly what the issue is - I have talked to a couple of people with these cats on their '04s without problems. Doug @ Crawford is suggesting I drive it for a few days as he has seen situations where the ECU adapts and the codes get cleared...and he's offering to replace them if I still have issues, so no complaints.

how do you like the plenum? I think it's a good mod, definitely noticeable gains above 5000 rpm or so.

 

A member here had simillar problem a while ago. Turned out that during the install techs screwed up one of the o2 sensors and that triggered SES. You need to check your errror codes to pinpoint the problem. Good luck.

***04 G35s 5AT/Sport***
***04 Volvo XC90 T6***

 

fyi this appears to be resolved. I had a fitment issue on the left-hand cat where the heat shield was contacting the bottom of the car. once this fitment issue was resolved, no more problems - the car runs great, and no more check engine light. my guess is that the contacting/vibration was somehow throwing a code (maybe knock sensor, I dunno) and causing the timing to be severely dialed back...but this is no more than a guess.