mpingitor

I have been having an issue with my 2004 F150 Crew Cab. I recently got a 77 Series K&N Intake system for Christmas. I installed it about a week ago and noticed some hesitation when accelerating from a roll. I went to pass someone and the truck was very hesitant and seems as though it was struggling and/or bucking. Then my check engine light came on. I took it to a shop where the computer said it was an issue with my mass air flow sensor. The guy at the shop said he covered up the filter with a rag and took it for a ride and it seemed to run better. He says the engine is getting too much air, is this possible? Has anyone else had this problem? He wants to put the stock intake back on to see if it eliminates the problem, any suggestions???? Thank you!

XLT Billy

I can't say I've ever heard of that. I had a buddy with an 04 civic si who liked to run just the throttle body because he thought it gave him more torque. Aside from getting a bunch of crap in his pistons because of not having a filter he never had the CEL come on. You should try cleaning the MAF with some of that CRC spray. I read about it somewhere else on the forums and tried it because mine was a little sluggish and she perked right up. Other than that I'm not sure. The filter doesn't have any holes or anything in it, does it?

GATORB8

Do you have a tune? It's pretty common for intakes and tunes not to play well together on the 5.4.

The mechanic's diagnosis pretty much sums it up.

mpingitor

There are no holes in the filter. It is brand new, but I still checked that out. And no there it does not have a tune. It is just a stock 5.4 with and exhaust system and now the K&N system. Does that mean I would have to get rid of it? I have a few other friends that have the same truck and same K&N system and theirs was fine.

techrep

iTrader: (1)

Did you oil the filter ?? Too much oil will fowl the MAFS...so I have been told.

kifels

x2 on the mass airflow sensor, clean it, try it again. if not you may need to replace it.

and is certanly worth your wild to find out what the code is.

you should not have any issues just puting on a CAI, especially K&N, it sounds like a MAF problem. did you drop it? touch the fillament? get it wet? not plug it in?

but like I said, get the codes pulled.

mpingitor

The filter came already with oil on it, I did not add any more to it. The mechanic said it threw a code for the MAFS. If it is the MAFS and the stock intake is put back on, it should still throw the same code, correct? He wants to try and put it back on and see if that fixes the problem.

kifels

If you are getting a MAF code, it will do the same thing with the stock intake. If I were you I would respectfully tell him he's an idot, go home and get yourself a can of carb cleaner or MAF cleaner and clean you MAF and see if it changes. if it doens't get your self a new MAF, your looking at about $150.00 from Rockauto.com, and change it yourself. I'm asuming you put you intake on and if you did you will have no issue changing the MAF.

unless of course he is doing this for free, which I doubt.

if you clean it and thats all it needs, your truck should ride smooth and your MIL llight will go out eventually.

mpingitor

That is what I thought. I did not think putting the stock one back on would change anything with it. He is a family friend who has a shop, so either he does not feel like dealing with it or he is missing something. I recently had a similar issue with the truck bucking when accelerating from a 50 MPH roll and the coil pack on the 8th cylinder was bad, that is what I thought was wrong this time. If I clean it and it does not throw a MAFS code then it should solve that issue of the hesitation during acceleration and all? By the way, I really appreciate the help.

xJimbos

Take the truck to Autozone and have them scan your computer for free.
Aside from the MAF code, do you get a cylinder bank lean code as well?

How does that K&N filter work? Does it hook up to the stock air box (without the drop-in filter part of it)? Is it a completely new assembly down to the throttle body with an insert hole for the MAF? I too would say pick up a can of MAF clearner at autozone or somewhere and clean it before trying anything else. When I bought my 5.4 used, the MAF in it had melted and I had to replace it. Look on ebay before you buy one somewhere else. Ford part is 240.00, I bought a new ford OEM MAF for 30.00 from someone on ebay. It may take a week or so to find someone selling one, but I bet you can eventually.

I'll tell you now, I don't know what that other guy was talking about with 5.4s and tuners not working well with intakes, but it is the other way around. Your 5.4 with a totally new intake will run leaner than normal without a tuner to bump up the gas injection (at least on certain types of intakes). (and even if you reset the PCM this happens) The 5.4s do not run lean if you use the stock air box because of how the MAF is situated, it can read the air flow better. (I have heard this from lots of different people with 5.4s) With new intake systems, at least certain ones, it seems as though the MAF isn't able to read the air flow correctly because the tubing is too wide or is angled weird and too much air gets past the MAF and the sensor cannot read all of it which causes your engine to run too lean. Bad for engine and other components.