I have had my Kand N CAI, TBS and Doug tune since the spring of this year. About a 2 months ago it started having an idling problem , but only after the car would sit all day or night. It starts right up, but after a few seconds, the idle drops WAY down to about 300 rpm, almost like it is going to die, then it shoots back up to 1000 and is fine after that. About a month ago, I took out the MAF sensor, sprayed it with brakleen and reinstalled it, seemed to run good for a few weeks and then went back to doing it again...today at work, it almost did not recover , it just sputtered and struggled for about 20 seconds , I am going to clean the sensor again tonight...I was thinking that maybe some of the oil from the preoiled K+N filter was contaminating the sensor.
Anybody got any ideas about this problem, any help will be appreciated!
Thanks, Dave

 

I had a similar problem that progressivly got worse. Turned out to be a faulty throttle-body that was replaced under warrenty. A couple of other people have also had the same problem.

http://forums.bradbarnett.net/showthread.php?t=49258

 

Well mechanically I would say that its something in the combustion chamber and once it burns its runs well. I would check your plugs first of all to see if any one spark plug or cylinder looks a little different than the rest. I doubt these are the problems but you could always have a leaking fuel injector that would cause that plug to be fueled up a bit, causing a rough idle for a second then its burnt up and all is good. Also If you have a slow leaking head gasket, if coolant or anything such as oil etc. is in the cylinder that is not supposed to be can cause this condition you speak of. So I imagine a throttle body issue can do it as well. Good luck with whatever you find out. But I would first pull the plugs, a lot of time that tells you a lot about whats going on with an engine.

 

oil separator time haha

 

As stated by 94tbird.

Look in the throttlebody area for oil which may be brought up through the pcv hose on the drivers side valve cover. This can accumulate in the intake tract and after a prolonged shutdown and finds its way usually to the rear plugs. It can also be valve seal oil leakage that makes it down to the cylinders.

 

Like I stated before look at the plugs, see which ones are the issues, and I would also look at the throttle body issue the others have delt with. good luck

 

check out my other post, on a similar problem
i've posted two vidoes showing the RPM fluctuating.. if that's what you got, then most likely a faulty TB is to blame

http://forums.bradbarnett.net/showthread.php?p=685456

 

Thanks everybody for the input...today I took off my CAI, I sprayed the inside of the TB with crc throttle body cleaner, also took out the maf sensor, and sprayed it down with the same. One of the things i did notice was that the air cleaner cone element was falling off.When I reinstalled the MAF sensor, I put low strength purple loctite on the two fasteners, they have been loosening up on me.
I also pulled the rear plug/ drivers side and it was fine.
So I go to start it up, and it took a lot of revolutions to start it, and now it runs terrible, almost like I am running on 7 cylinders,or a vacuum leak... I thought maybe it was the spray I used inside the TB and maf, but the problem will not go away,
I do still have the TBS installed, can I test the system for leaks by spraying it with ether or something that would make the idle spike or die if it found a vacuum leak, will this old school tecnology work in this modern car?
I am baffled as to why the car is now running like S##t now...any constructive suggestions???

 

You definately need to be careful of over oiling your filter. The MAF sensor is REAL sensitive to this. Just this last weekend my car totally shut down after getting on it hard. When I pulled over to try and start it again it idled very irratically, and would bog down if I tried to give it any gas. The check engine light also came on, I hooked up the SCT for the DTC, got a P0171 and P0174 (Lean condition). Turns out the MAF sensor got contaminated with a little filter oil. Once I cleaned it with air spray (the stuff you use to clean PC keyboards...) everything was back to normal.

 

Im going through a similar problem right now. After I installed my CAI/Tuner combo from Brenspeed I noticed that if I was in 5th gear cruising at around 65+mph and then put it in neutral and started to slow down, say for a stop light, the RPMs would drop to about 300 then sort of pulse up to 800 as if to keep the engine running. Today it was doin the same thing but it died! Any idea what the problem could be?

 

Well I found the reason was running like S##T, I bought a new plug and replaced the one I took out, runs great now...must have cracked the plug internally taking it out, I also am amnazed Ford did not use any anti seize on the plug threads from the factory!!!BTW, Ford wants 20 bucks per plug, Advance auto charged me seven for the exact same plug!
Since one of my cylinders was not firing correcetly, I am amazed that I never got a light...do you guys think that is normal, should I have gotten a light???

 

Thats interesting. I checked on one of my plugs just to look to see how they were doing. It looked fine.. Replaced the plug back in and after that my idle was crap. It would miss every .25 second or so. So I believe I busted the plug somehow when I looked at it. WHich makes no sense. I replaced all 8 plugs since I had 46k on em. All was well after that. We both had the same thing happen when removing the plug. Weird.