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Question is Did you have a cold air intake (or drive a little while with one on) without cpe fix? Basicly while it was lean. Because I was told the engine runs very hot while lean and causes the cats to pre-maturely fail. Basicly it was my fault the engine blew is what mechanic said.
 

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Mine was completely stock.
 

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I have a K&N semi-cold air intake (short version). I have not done anything that tricks the computer or changes to the computer. On my DYNO run, the guy also did an air/fuel ratio (stuck a sensor in my tailpipe). Up to 4000 rpm the air fuel is about 14.8 to 1, after 4000 rpm it changes to 12 to 1. The guy said it was good. This was done shortly after I had a 2 1/2" Magnaflow rear cat installed (1/4" above stock). He also re-worked the bad stock exhaust in front of catalytic (bad sharp bends) from 2 1/4" to 2 1/2". This new exhaust flows better and should release back pressure up to pre-cats! I believe the stock exhaust is not flowing enough causing strain on pre-cats. I am hoping. I have pics of old exhaust issues. My engine hasn't blown, but Mazda did change pre-cat with exhaust manifold when I only had Mazdaspeed cat-back exhaust at that time (mis-fire code).
 

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so does the cai cause our cars to run lean or even the airbox mod? i got the airbox and my take off suck with the AC on, i wasn't sure if my AFR was off a lil. no CEL though. i was hoping not to destroy my cats as well
 

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The CAI did not cause your engine failure. The precats clog up and destroy these motors stock.
 

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o wow, that's hell. i know most people on here had multiple misfires that killed their motors. i had one every now and then even after swapping my plugs for about 3 mos before i found the bad coil. i had a coil with a cracked housing, i replaced it, problem solved!
 

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I had a bad coil causing a misfire that started to melt the precat. Car was 100% stock.
 

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I've got a 2003 6 V-6 ATX w/90K, original owner (Purchased07/03)
CP-E CAI non-customizer, MazdaSpeed cat-back exhaust, Fluidamper, CP-E engine mount, CP-E tranny stage 1 mod, AWR comp radiator, largest oil and tranny coolers available, coolest possible thermosat available, Water Wetter, TB bypass mod, Mobil 1 5-20 oil w/KN oil filter (higher flow). Changed oil 3-4 times a year, tranny flush once a year w/Mobil 1 in both every time. Stock coils w/no CEL misfires, PCV valve checked ok. The car still runs hot, not on the temp gauge, but on the amount of radiated heat around the engine bay. The air coming out of the outside vent setting for the cabin is always warm to hot. The tranny runs really hot, 200+ degress on idle (known Jactco issues). Car was fine, no oil or coolant loss, no CEL's, until just after trip to Pagosa Springs, Colorado from Chicago. Oil consumpsion skyrocketed really fast. Pre-cats plugged and honed out one of my banks. Oil constantly full of gritty carbon and ceramic material. No amount of engine flush, oil change, oil type or weight change would clear it up. Had to replace motor, exhaust, coils, plugs, fuel injectors, thermosat, rebuilt tranny, axles, new fr. wheel bearings, changed to Amzoil in motor and ATX. 7k in total. Car has design issues w/ PCV valve, coils, and pre-cats. All WILL cause engine failure after 60K. Stealerships in Western Chicago suburbs were extremely slow to understand and finally admit these issues. Be warned of these problem areas and swap out OEM parts ASAP with proven replacement parts NOW if you wish to save thousands later.
 

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I've got a 2003 6 V-6 ATX w/90K, original owner (Purchased07/03)
CP-E CAI non-customizer, MazdaSpeed cat-back exhaust, Fluidamper, CP-E engine mount, CP-E tranny stage 1 mod, AWR comp radiator, largest oil and tranny coolers available, coolest possible thermosat available, Water Wetter, TB bypass mod, Mobil 1 5-20 oil w/KN oil filter (higher flow). Changed oil 3-4 times a year, tranny flush once a year w/Mobil 1 in both every time. Stock coils w/no CEL misfires, PCV valve checked ok. The car still runs hot, not on the temp gauge, but on the amount of radiated heat around the engine bay. The air coming out of the outside vent setting for the cabin is always warm to hot. The tranny runs really hot, 200+ degress on idle (known Jactco issues). Car was fine, no oil or coolant loss, no CEL's, until just after trip to Pagosa Springs, Colorado from Chicago. Oil consumpsion skyrocketed really fast. Pre-cats plugged and honed out one of my banks. Oil constantly full of gritty carbon and ceramic material. No amount of engine flush, oil change, oil type or weight change would clear it up. Had to replace motor, exhaust, coils, plugs, fuel injectors, thermosat, rebuilt tranny, axles, new fr. wheel bearings, changed to Amzoil in motor and ATX. 7k in total. Car has design issues w/ PCV valve, coils, and pre-cats. All WILL cause engine failure after 60K. Stealerships in Western Chicago suburbs were extremely slow to understand and finally admit these issues. Be warned of these problem areas and swap out OEM parts ASAP with proven replacement parts NOW if you wish to save thousands later.
My engine seized on the interstae after heavy rattling. It had 64k miles on it. I replaced it with a Jasper engine cause of the 100k mile / 3year warranty they include. Before getting new engine installed my steering wheel was rattling real bad especially in D,also hesitation and rpm jumping at idle. I'm getting the ignition coils and PCV valve checked after i hit the 500 mile mark for the 1st oil change, also will be flushing the tranny at that time to rule that out as well. After i get all that replaced i am getting rid of the entire OEM exhaust system. thinking about CPE headers and magflo CBE. anything reccomnedations or advice for this.
 

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So it's agreed that the airbox mod should not cause any reason for the pre-cats to fail?

Also, does anyone know if installing CPE headers will cause increased emissions and emission test failures? I wouldn't think so since we still have the main catalytic converter, but want some opinions before I make the change. What about the CPE high-flow cats?
 

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sorry completely forgot to answer your question.
YES i ran with a K&N CAI for a while and its started going down hill. great intake horrible OEM exhaust system i will be replacing everyhing exhaust wise as so the OEM system doesnt even think about touching my new engine...

SkiMoab thats crazy i was born in provo back in 1990 live in bama now but i come back to visit alot.
 
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