ucdavisboy

Okay....just my luck. I installed a K&N Filtercharger on my 2004 V-6 last week (no tune).

A couple days later I noticed that, when I would let off the gas (particularly at speeds above 40 mph) the engine feels like its bogging down or stuttering. Even when I have the cruise on and I go down a small incline, the cruise will pull off the throttle and there is the bog/stutter again.

Now...I have been told that the K&N is a "no-tune" intake....but I have read that, due to the increase in the intake size that there is simply no way for the cars computer to compensate for the increased airflow without a tune (in other words, telling the computer 'give the engine more fuel to compensate for the extra air stupid').

Anyway...this is new ground for me and it bugs....I'm ready to yank the filtercharger off and re-install the stock system because I want the car to feel normal.

Also....if it does sound like a tune is needed, how does one go about doing that AND how much $$$$$$ for it.

Thanks in advance

UPDATE!!!!

Upon further research there is some suggestion that the issue may lie with the MAF (Mass Air Flow Sensor). Apparently it getting dirty is a common issue with K&N eqipped cars (particularly NEWLY equipped cars). I guess the oil on the filter, especially new oil (which mine is) has a tendency to evaporate and dirty the MAF. If this is the case, that would explain why on the first day it didn't stutter but now it does after several days.

I am going to clean the MAF (I know....be careful) and see if that solves the problem.

TJ4Cam

Yes, with an oiled filter you must pay attention to the MAF wires!! Let us know if that did the trick for you or not.

tacbear

If cleaning the MAF doesn't help, the disconnect the battery, mash the brake pedal 3 or 4 times and wait 30 minutes then connect the battery. Now take her for a drive and the computer should adjust for the CAI.

elcaminoguy

I've used K&N filters for years on a number of cars. There's a K&N FIPK on a 2003 avalanche in the driveway too and it hasn't caused any issues for the last 40K miles.

There's strong opinions on both sides of the aisle on this and it's been suggested that some dealers will try to void a warranty if they find a K&N filter installed. Here's K&N's stand...

http://www.knfilters.com/faq.htm#7

Anyway, it's not like the filters are dripping oil to start with. I'd lean more toward the tune. If the oil evaporated at such a rate to coat a MAF sensor there wouldn't be much oil left in the filter to be of much use in filtering anyway. You'd be throwing POxxx codes too.

I have/had them in 2003 Avalanche, 95 Formula, 96 Camaro V6, 74 El Camino and 69 Firebird. No issues and the 69 Firebird is a Fuel Injection conversion on the stock Pontiac bottom end.

SSilver0702

Did you reuse the circular mesh screen from your stock intake? If you did, where did you place it?

Diagram of FIPK setup:
throttle body>FIPKII intake tube>MAF housing>MAF mesh screen>heat shield>filter...( I dont have the 6 anymore, but I 'm pretty sure that's the order ).

It could of just been in my head, but it seemed to make a difference on what side of the heat shield you placed the screen. I originally tried it with out the screen and the car would buck a lot when I let off the gas, so I decided to keep the screen on. Well, hope this helps and if you want to read more you can check out this thread on 3.8:

http://www.3.8mustang.com/forum/showthread.php?t=54533.

Blake

elcaminoguy

You mean on the Avalanche?

On my 96 Camaro I used the stock snorkel setup with a K&N OEM drop in. It did have a screen on the front of the throttle body. You'd have to pretty much destroy it to get it out and it didn't really help performance much if you did that. In fact it actually seemed to straighen out the airflow into the butterflies which is always a good thing.

ucdavisboy

Thanks Blake!!!!! Yes!!! I wondered what that silly screen was for too. I will be re-installing it in front of the MAF tonight as that appears to be "the" solution.

Anyway, I did go and pull the MAF last night and spray it like crazy with the electrical cleaner. I also unhooked the battery and emptied the brake lines as suggested. Well-this morning---------very little bucking. The car seemed to buck a little when I would do something new, like let of the gas at 70 vs. 50 or let off right after acceleration, but as the drive went on it seemed to learn how to regulate the airflow. Even so, it still seemed like the throttle and engine response was jumpy so I am guessing the screen being missing may be the culprit. Oddly, the K&N install sheet for this FIPK does NOT state that said screen should be reinstalled (?????). Any thoughts on how restrictive the screen might be to the airflow??

As to elcaminoguys comments on the evaporation of the filter oil: I purchased a used FIPK and the filter was dirty enough to warrant a recharge. I oiled the filter and probably drove the car within an hour (not the best choice considering I really soaked the filter) so I am guessing there was some blowback past the MAF. That being said, there is a school of thought that believes that the combo of the less restrictive oiled filters (letting in more particles) and the oil coming off them over time as a pretty large impact on the efficient workings of modern (another word for overly sensitive) MAF's. These people generally ascribe to the rule of cleaning your MAF every 6 months or sooner depending on milage/conditions.

Thanks to ALL for their info...it was invaluable and I will let you know if the screen evens everything out.

SSilver0702

I'm not sure how restrictive the screen but, according to what I've read, the screen helps to smooth out the airflow before it hits the MAF sensor. I also made sure to clean the MAF sensor with the electrical cleaner, but never noticed much of a difference.

RED STUD

Sometimes it will take 3-4 weeks for your cars computer to fully compensate for the amount of air now enterting. What you are doing is fine.

ucdavisboy

Adding the screen did the trick. The car idles and powers like a dream. Funny what a difference such a little thing can make.

Katshot

The screen can be left out of "some" cars while others really need it. The reason is that different intakes have different flow characteristics. By "intake" I refer to the entire air inlet system, from filter housing to engine. Due to differing "packaging" of the air inlet system components by the OEM, certain "issues" can be created by less than optimal system design. The screen makes up for a lot of the negatives by smoothing and diffusing the inlet airflow. This creates a more consistent sample for the MAF. This is why some cars seem to tolerate the removal of the screen better than others.