I followed the instructions on how to make my own midpipe and HAI, and I put everything together properly making sure there were no leaks. However, it has been about a week since I installed it, and now my max has start-up and idle problems w/no CEL coming on. The start-up problem is this: whenever I start the car (after a few hours) the rpm goes up as normal then suddenly it drops down to ~450 rpm and slowly raises back to normal idle. That is when my idle problem occurs. At idle(~600-700rpm), the engine shakes some like it is either running rich or lean. The exhaust vapors seem to be the same during idle(no black smoke or sputtering), no CEL code, and I cleaned/protected all of my sensor connectors along my intake. The gas mileage has not suffered much, and It runs fine throughout acceleration, but I do not want this seemingly small issue turn into a financial crisis. thanks for any help/replies

 

The idle problem also occurs at stop lights and such, thanks.

 

Did you use a breather filter? A few people reported such problems and the associated it with the breather filter, I don't know why but they did. I use a breather filter and it caused to such promlems.

You may have a leak you don't realize or it could be caused by something totally different. Dirty TB, PCV valve, TPS,......

 

I used a breather filter for the hose coming from the valve cover. I have not checked my PCV, but I have cleaned my TB and IAC fairly recently(last 400 miles). I sealed questionable areas with silicone. I didn't hear about people having problems w/their breather filters, I tried to search for "custom intake problems," but maybe there is a better phrase that I could use. thanks for the reply

 

Happens to my Stock Maxima, A lot of people have this problem, Just search about it, let off on your car a little let it rest, or it means OIL CHANGE TIME

 

Have you cleaned your throttle body yet? I am fairly certain your problem is caused by deposits left from tens of thousands of miles. Cleaning it is easy.

Try maximadriver.com

 

I changed my oil about 800 miles ago, used the correct filter, and cleaned my TB and IACV about 400 miles ago. I always use 93 octane (chevron or shell), and I used a fuel system cleaner at the oil change. This problem did not begin until I installed the intake pieces.

 

It shouldnt be related to the intake. But just raise your idle and then everything will be ok.

 

i have a hybrid HAI using a crankcase filter and i've noticed the same problem. althought i'm thinking it might have to do with cold weather. it didn't do it when i installed everything last summer/fall, but as soon as the temps started dropping into the 30's i noticed a rough idle @ lights. and on the few days that it has been warm lately, it idles fine. so who knows? but try putting your stock intake back on and see if you get the same thing... or just run another hose to the intake instead of using the crank filter.

 

Your car won't idle right if you're using breather filters for both the front and back. The hose from the rear bank needs to be plumbed into the intake in order to get keep everything working correctly.


Dave

 

Thanks for the replies. My idle has slowly gotten better on its own(?), but it's still not 100%. And I only used a breather filter on my "crank case." thanks again, peace

 

I think your ecu is learning now theres more air and theres a breather filter on the crankcase thingy.... give it some time and I bet it will get better