I have an "02" TL, non - S that I just put a K&N filter in. It has a sort of "coughing" problem when I first start it, but then it immediately goes away after that. I also get horrible gas mileage in the city - 14mpg! I called K&N and they said to disconnect the negative battery terminal for 1 hour - I did, but it didn't help. Any suggestions out there?

 

Dude,

I'm not a mechanic...but what does disconnecting the battery have to do with this?

Is the filter the same size as the stock filter or is it one of those cone-like K&N filters that sit out in the open? Just curious.

 

I'm not a mechanic...but what does disconnecting the battery have to do with this?

This would clear out the car's computer. The computer continually makes adjustments based on atmospheric conditions, fuel used and driving habits. Although I'm not sure if it would help in this case. Sounds like it's not getting enough air.

For those of you who remember the old cars with carbs. When the engine was cold (startup) the butterfly on the carb would open to allow more air in until the car would warm up. Once warm, the butterfly would partially close and reduce the air mixture. If the choke wasn't working right and the butterfly wouldn't open when cold, the car would cough and sputter until it would warm up.

Is it installed properly? Is it getting enough air? Just a hunch.

 

Did you install it right? Hope you didn't leave anything extra in there.

 

You took it out of the bag, right? j/k :p I've had a K&N drop in for a couple months and its been fine. And I didn't disconnect the battery.

 

You're supposed to take it out of the bag? Just kidding! Yes I took it out of the bag, and nothing else is in there that I am aware of. It opened it back up and checked the installation again, and everything appears correct. Even if I were to deal with the problem, it does seem to have improved the throttle response and performance - or maybe that's just in my mind - but what about the gas mileage problem? Do any of you get only 14 mpg?

 

There is another current thread on both the TL and TL-S forums that is discussing the mileage issue. Big Ped started the most recent one. There have been others.

My TL-S has a small backfire (pop) on startup sometimes. It also coughed once that i noticed. Dealer said the pop seems to be a normal attribute of both TL models and the MDX. I am keeping an eye on it.

 

Thanks for the info. I will probably just deal with it, because it does seem to help the performance - barring the gas mileage issue.

 

I usually get about 20-22 mpg in a mix of congested suburban streets and highway traffic. My work commute is about 20 miles, so I don't have the car cruising for very long.

The worst performance I've seen is 16 mpg when I started flooring the pedal to get on the highway and passing people. I drive more sedately now and I'm back to the 20-plus mileage range.

 

one question, is the K&N filter just a replacement filter or a High flow filter that replaces the OEM filter?

I got the comptech High flow filter and I love it.

 

I don't believe the noise you're hearing is associated with the installation of the K&N filter. After making any change we become keenly aware of every noise the car makes. What you're hearing at start up is most likely the vacuum operated lower engine mounts. At start up there is no vacuum available, so the mounts typically make noise.

 

The computer constantly adjusts based on your driving habits, atmospheric conditions, etc. There is no need to disconnect the battery trying to reset the ECU after mods.