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Discussion Starter #1
so, i have pretty noticeable vibration in my steering wheel and floorboard from the engine during idle...whether that be in D or P. i have had it since new but seemed to have got a little worse after i installed my Nismo intake at about 1k miles. my MAF is clean as i have checked and cleaned it twice. i took it to the dealer at 2k and they checked my fuel/air ratios and said it was "good" but reset my ECU anyways...or so they say. i idle in D at about 500-550 and in P at 650-700 once everything is warm with no fluctuation. when the engine is cold, it fluctuates +/-100rpm but soon levels out. when the air temp is cold, humid, or raining, the truck idles with an even more noticeable vibration. the intake is all i have added. wth is going on?? am i running lean or something or is my harmonics off? dealer says the vibration feels normal but my 08 idled so smooth i could barely tell it was running. is there a way to check my voltage output of my MAF sensor? thanks in advance:)
 

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your idle speed is too low. check for leaks in your intake system, especially down stream from the MAF sensor. Be sure the PCV hoses are secure, and you may also want to check your PCV valves to see that they are clean and operating freely. Remove them and wash in a solvent. If you shake then they should rattle.
 

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Nissan spec at operating temp is 650 +-50 RPM in park and 550 +-50 in drive. Every Titan I checked when doing timing advances was at 630-650 in park.
 

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Discussion Starter #4
my 08 idled at the same rpm which is why im a liitle uneasy about this vibration. i understand at lower rpms the harmonics get thrown off a little and cause this. its more than normal...especially on the weather conditions posted above. when warm (80+deg) it is much less noticeable. trying to figure the reasoning for it. were are the PCV valves located...under the engine cover?? the two tubes that run of the intake tube are for the valves correct? im pretty sure those are not leaking because they were SOOO hard to get joined when i installed the intake. they are extremely tight. the urethane sleeve deal that goes around the intake tube and throttle body seems to be leak free. hard to tell since the engine is so loud. but i dont see or feel any ripples or imperfections.

btw when the engine has been running a while, its warm outside, and only when traveling at low speeds(stop and go traffic), my idle has actually dropped to about 450. should i have my idle upped a little and see if it helps? also in between 1200-1600 rpm in P, the engine shakes pretty hard. never thought much of it since there was no load applied.
 

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There are two PCV valves. They are located at the rear of each cylinder head. If you are you are leak free, do an idle air volume learn. That should straighten out any uneven idle and cure the vibration.

Idle Air Volume Learning (Throttle Position Learning) http://www.clubtitan.org/forums/showthread.php?t=3481&highlight=idle+air+vol+learn
It is better to count the time accurately with a clock.

Operation Procedures
1. Perform “Accelerator Pedal Released Position Learning”.
2. Perform “Throttle Valve Closed Position Learning”.
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Conform that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.
7a. Fully depress the accelerator pedal (HARD)
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.
 

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Discussion Starter #6
so i checked the urethane sleeve and all the other hoses and connectors again. as you can expect it all looked brand new and perfect. but, i took a mirror to the bottom side of the intake and realized that the metal tie was a little bent and i could see an opening in the sleeve. so i replaced the tie and as soon as i started the truck it sounded different. the inconsistent injector sound is back. idk how that was related but ok, i dont mind, kinda like it lol?? unfortunately, it didnt solve the vibration. going to try the Idle Air Volume relearn in the morning.

btw i did find the PCV valves. is there any special precaution with removing them and how would i be able to tell if there is a leak? thanks
 

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Discussion Starter #8
i know my idle is good...i wasnt worried about that. mainly just for info for you guys to help figure out the vibration. figured it might have played a role since the harmonics get thrown off a little at low rpms. thanks though
 

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i'm gonna dust this one off and bring it back up. I'm running just slightly under 500 at idle, but its about 60 degrees out. i too have started to notice alittle more vibration. could it be the weather? if not, i think i need to check my TBS i just installed a few weeks back. also, does anyone ever use throttle body cleaner in their trucks? i've never seen a thread where anyone has cleaned their throttle body. thnx.
 

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also, it is the airaid tbs.
 

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Discussion Starter #11
mine is much more noticeable when its under 55-60deg(mornings mainly) and when its raining or muggy outside.

i tried switching out to the stock intake and drove it around for a day with no luck...exactly the same. that was actually to track down a fluctuating rpm. i also did the idle air relearn with no luck on the vibration or rpm issue. taking it in tomorrow. i did notice if i tap my steering rod up just a wee little bit, i can feel and hear it hit something behind the firewall...i wonder if that might be the source of the vibe?? going to bring it up when i take it in.
 
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