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CAI/Tuning

3K views 8 replies 4 participants last post by  pzr2874 
#1 ·
Hey guys, I just joined today and I'm hoping you guys can help me out. Ive been having a problem with my 04 wrx and its check engine light. My hypothesis is that the MAF sensor is freaking out because it has an aftermarket CAI, at least that's what Ive gathered from looking around here. I guess it's a typical problem for these after market CAI's? Anyways, one problem is i dont know what kind of intake it is, it came with the car when i bought it. Ive tried fidgeting with it, tightening it up fixing vacuum lines (which since its older were kind of beat up) but its still throwing the code. SO that brings me to the question for you guys. I really just want to buy a whole new intake so i can say bump this one and get one that i know wont throw a code. Ive seen Cobb and SPT come up a lot on here, but theres been a lot of controversy saying that the cobb might crack in some spots and SPT still requires tuning ect. I'm just wondering what would be the best option. I guess i dont mind getting it tuned, i could probably do that for my current intake, but it looks like one of those mass general ones you could buy at autozone or something cheap. Another problem is trying to find a place around here that could actually do a tune. Anyone know how much a tune for the CAI could run? Maybe its better to just get the tune instead of a whole new intake since it might be around the same price? Input and thoughts appreciated.
 
#2 ·
Unless you get the OEM intake, whatever you get will require a tune. Most the intakes make the car run dangerously lean in the midrange due to the bend in the OEM intake, top end will be close as long as the diameter of the pipe is the same. Also, if it's a "build it yourself" CAI, it's possible it has a bigger MAF housing, which will REALLY throw things off. I would first figure out if the check engine light is throwing a lean or rich code before you did much. If you don't know the history it's possible the car is tuned for the intake already.
 
#4 ·
If it's just a 'cat-back' system it shouldn't affect the tune at all, if it's a downpipe and it's not tuned you could have bigger problems than just a lean code. A vacuum leak could cause the lean code as well, but typically vacuum leak will have other symptoms as well, high idle, problems idling down, stalling etc. It sounds like it needs to visit a tuner to me.
 
#5 ·
well you nailed that on the head. Thats exactly what it was doing when i found that the vacuum line coming off the intake was hardened and cracked, basically broke in half. It was stalling randomly when i slowed down to a stop light. i fixed that and reset it and its better. It still stalls randomly now, but its way more seldom. For instance it only stalled once today at one stoplight as opposed to every stoplight. But i have noticed that one i slow down to pull into my drive way, or stop light shifting out of second and putting it in neutral thats when it likes to cut out. And if it doesnt stall then sometimes itll almost sound like a faint spudder and then other times it wont do it itll just go back to natural idle.
 
#6 ·
My car kinda does that... Its never actually died but if im in the gas and get out and put it in neutral real quick if theres a light or something my rpms drop and almost dies then raise and stay consistant.. Only happens right after i put it in neutral though.. And it did it when it was bone stock now i have a dp and exhaust and it still does it but i just dont notice it anymore. It has never died once though. I wouldnt even know where to begin to start.. Maybe plugs??? does the car lag just barely if you rev it while sitting i think that means your plugs arent good im not sure though someone will jump in and correct me if im wrong though:)
 
#8 ·
Would have to see your current setup to answer that one intelligently. If whatever is in there now looks like it is going to hold up and there aren't any crazy bends or spots where it is going to blow apart, probably no advantages to speak of, other than having a name brand sitting under your hood.
 
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