Serious mpg loss?! wtf?
Junior Member
Joined: Aug 2008
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I just got throught installing a K&N CAI in my '05 5.4 and lost about 2 mpg on the highway. I also followed the direction to the T and made sure the mass air sensor wasn't touched at all. I don't get it. I made sure that I tested the mileage at the same speed, windows down and no a/c, etc just to make sure that all the variables stayed the same. I don't have an exhaust yet, but that still shouldn't have a negative effect on my mileage.
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Member
Joined: Aug 2008
Posts: 35
Likes: 0
From: Oklahoma
See, it just really doesn't make sense to me that it reduces your mileage...I mean, I did a few other minor things to help the mpg's a little bit (like exhaust, constant tire pressure monitoring, etc...) and everything I've done has helped in one way or another except for the CAI.
Now I'm finally breaking down and considering a custom tune...I just have a hard time dropping 400 for a gryphon or something equivalent unless it is almost guarateed to have positive effects without being detrimental to the health and well-being of the vehicle...
Now I'm finally breaking down and considering a custom tune...I just have a hard time dropping 400 for a gryphon or something equivalent unless it is almost guarateed to have positive effects without being detrimental to the health and well-being of the vehicle...
Senior Member
Joined: Aug 2008
Posts: 4,778
Likes: 10
From: Douglasville GA
I think that their is a problem with 5.4 3 valves running lean after installing an aftermarket CAI. It doesn't happen to 100% of all 5.4's but a good majority do end up with this symptom. This will include less MPG's and possibly a check engine light. The only way to cure it is to get a custom tune, Edge, Gryphon, etc. It'll end up costing you around $400-$500, depending on the brand, and yes they do have multiple settings.
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Member
Joined: Aug 2008
Posts: 35
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From: Oklahoma
This is getting to be ever more ambiguous... 
So it boils down to being luck of the draw with CAI's causing lean conditions? Mine didn't ever trigger a check engine light or anything...
I used to be skeptical about custom tunes, but now I'm doing the research. I've emailed PHP a few times asking questions and what not...I think as soon as I can come up with 500 bucks I'm gonna order one with the 87 economy (?) tune and another one to tear the streets up with every once in a while
Anyone have suggestions on what tunes to get from PHP?
So it boils down to being luck of the draw with CAI's causing lean conditions? Mine didn't ever trigger a check engine light or anything...
I used to be skeptical about custom tunes, but now I'm doing the research. I've emailed PHP a few times asking questions and what not...I think as soon as I can come up with 500 bucks I'm gonna order one with the 87 economy (?) tune and another one to tear the streets up with every once in a while
Anyone have suggestions on what tunes to get from PHP?
Member
Joined: Apr 2008
Posts: 77
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From: California
I think..
Ya I do have a cat back SIDO exhaust job. And, yes, I did reset the battery like the instructions said. I did look at the MAF sensor when I was putting the factory intake back on and it wasn't oily or anything.
About a custom tune...how much would a good one cost me? I'm just a college kid, dropping 270 bucks for that intake was about all I could handle for a while...luckily the manufacturer was cool enough to refund the money. I'm not looking for gobs of power or anything...just a few extra mpg's, thats all. But if its possible, could a guy get one with a few different user changeable settings with different parameters to adjust for fuel mileage, power, etc...? It would be kinda neat if I could just push a button and go from getting 23 mpg to shredding my tires off the wheels (just to blow the cobwebs out, of course
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I appreciate all of your feedback! Thanks...
About a custom tune...how much would a good one cost me? I'm just a college kid, dropping 270 bucks for that intake was about all I could handle for a while...luckily the manufacturer was cool enough to refund the money. I'm not looking for gobs of power or anything...just a few extra mpg's, thats all. But if its possible, could a guy get one with a few different user changeable settings with different parameters to adjust for fuel mileage, power, etc...? It would be kinda neat if I could just push a button and go from getting 23 mpg to shredding my tires off the wheels (just to blow the cobwebs out, of course
)I appreciate all of your feedback! Thanks...
I get 19-21 mpg on the freeway running at 64 mpg in the flats unloaded and it might be more but most times I am no going very far without my trailer to really tell. 12.5 mpg with my trailer with no hills, 11 thru the mountains.
Senior Member
Joined: Nov 2005
Posts: 17,118
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From: Burleson, Texas
Guys feel free to correct me if I'm wrong on this.
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Member
Joined: Aug 2008
Posts: 35
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From: Oklahoma
Good lord...I'm right at the intersection of confused and don't what to do. 
I've heard all sorts of talk about how a CAI with no tune will make you run lean, and then have people say that they had absolutely no trouble with them with no tune. Then I get one and lose mileage, then hear all of you saying that you gained mileage (even those of you with no tune). This is nuts...my head won't stop spinning
I've heard all sorts of talk about how a CAI with no tune will make you run lean, and then have people say that they had absolutely no trouble with them with no tune. Then I get one and lose mileage, then hear all of you saying that you gained mileage (even those of you with no tune). This is nuts...my head won't stop spinning
Senior Member
Joined: Aug 2008
Posts: 4,778
Likes: 10
From: Douglasville GA
Good lord...I'm right at the intersection of confused and don't what to do.
I've heard all sorts of talk about how a CAI with no tune will make you run lean, and then have people say that they had absolutely no trouble with them with no tune. Then I get one and lose mileage, then hear all of you saying that you gained mileage (even those of you with no tune). This is nuts...my head won't stop spinning
I've heard all sorts of talk about how a CAI with no tune will make you run lean, and then have people say that they had absolutely no trouble with them with no tune. Then I get one and lose mileage, then hear all of you saying that you gained mileage (even those of you with no tune). This is nuts...my head won't stop spinning
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Member
Joined: Aug 2008
Posts: 35
Likes: 0
From: Oklahoma
I'm just taking a shot in the dark here...3 valve means 2 intake valves and one exhaust valve, correct?
If so, do the issues arise from breathing in more air than the engine and exhale? Sorry if thats a dumb question...like I've stated many times before: I'm not a mechanic
To go further, would the problem be solved if it were, say, a 32V (4 valves per cylinder)?
If so, do the issues arise from breathing in more air than the engine and exhale? Sorry if thats a dumb question...like I've stated many times before: I'm not a mechanic
To go further, would the problem be solved if it were, say, a 32V (4 valves per cylinder)?