2002 Sentra 1.8...huge idle problem..HELP!!!!!!

[davidpark9677]

Hi everyone, I am new here. I have huge problem. I have 2002 Nissan Sentra that's idling bad even if its at Park or Driving mode. When it's at park it goes up and down slightly and vibrates the whole car around 750rpm and when it's at drive it idles around 500rpm. I have had this problem for a while now. don't have a clue what's wrong with it. Here are the things that I've done

-Front and Rear Cat converter

-new computer

-4 o2 sensors

-new spark plugs

-MAF

-reset idle

There is no air leak at all, I've been told it's the timing chain might need timed, or getting it replaced. Checked and see if it was misfiring any cylinders, and it's not misfiring any cylinders. Don't know what could be the problem. BTW just yesterday, checked spark plugs again, it was burnt. Need new spark plugs in 2 weeks!!! this is outrageous. Somebody please help me!!!

P.S. It drives fine. I've just made another 5 hour trips through mountains, however the gas mpg sucks.

[Faja]

Try cleaning out the TB and IAC Valve.

[davidpark9677]

Try cleaning out the TB and IAC Valve.

Hey, thanks for tips, but I ain't no mechanic. what's TB and IAC valve stands for?

[Faja]

lol........

Throttle Body and Idle Air Control Valve. Google those 2 items and you should find some tips and videos on how to do it.

[ABNRML4U]

I just like to day Welcome to NicoClub! Everyone here is nice and cool Enjoy and don't become a stranger. Take Care and Happy Hoildays.

[davidpark9677]

Thanks Faja, Well, I've went to autozone and bought a STP carburator<?> cleaner and cleaned and brushed throttle body and Idle Air Control Valve today. Here's what happend, the idle has gotten better, but only in P and N mode. if I put the car in R or D mode it still idles up and down between 500 and 750, and if I give it a little gas up to 1500, than it idles like crazy. I spoke to one of the mechanic guy over at the pepboys and told me to brush the hell out of EGR valve, any suggestions? I hope this isn't a big problem...

10:30PM Another Observation

I took the car to make run to Walley World, and I found something funny. Whenever I am sitting and just tap on the gas, like I said, it runs from 1500 to 1800, and when I give it a gas little more, it feels like RPM 2000 to 2500 does not exist at all or feel like it's skipping between 1800 to 2500. Any Ideas on this anybody? Any suggestions that wouldn't cost me bunch will be greatly appreciated
Modified by davidpark9677 at 7:43 PM 12/26/2009

[Faja]

Now that they are cleaned, do the "idle relearn" procedure for your car.

You must follow this procedure exactly as stated:

Warm up engine.-Turn ignition switch ?OFF? and wait at least 10 seconds.-Confirm that accelerator pedal is fully released, turn ignition switch ?ON? and wait 3 seconds.-Repeat the following procedure quickly five times within 5 seconds.a. Fully depress the accelerator pedal.b. Fully release the accelerator pedal.-Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stopsblinking and turned ON.-As soon as the MIL light stops blinking and comes on solid, release the accelerator pedal and start the car.-Allow the car to idle for approximately 5 minutes.

[davidpark9677]

Thanks again Faja, cleaned EGR valve and it drove fine, but still idling very slightly. However, after all the cleanings and installing new spark plugs, because they were burnt, I tried to let my car relearn idle by following the procedure you have instructed me to follow. I have followed precisely what you have written, and funny thing is, my MIL light (assuming it's Check Engine light) is keep blinking. It never stops remaining ON. I've held my accelerator down for next two minutes and still blinked, never came on solid. I took it to autozone once again, they told me it's misfiring constantly. Any other solutions? do you think I just need to replace the whole parts?

Something I tried for fun today, I've went watched video for "how to test your EGR valve" at youtube. It told me to cut aluminum can way valve hole looks like and block it and drive it around for while, so I did it. Funny thing was, it drove fine, not even idling at all, but it idles at 1500 RPM and if it catches misfiring, it will idle up and down at 1500 to 1700RPMish. However, didn't have new spark plugs when I was trying this. any other suggestions? do you think I may need new coil? sigh....

[Faja]

If the MIL keeps blinking, either you're not doing the procedure correctly (timing has be very exact - either use a stopwatch or get someone to time you) or maybe something else is wrong. Keep trying it and see if you can get the MIL to stop blinking when it's supposed to. Other than that, I've run out of ideas as you have tried several of the others already.

[davidpark9677]

Thanks Faja, I finally took the car to the shop and paid for diagnostics and found out what was causing the problem. It was Cam Sensor, Crank Sensor, Spark Plugs, and EGR valves. Well here's the problem, I bought the cam sensor and crank sensor, but they look exactly the same. I wonder if Cam sensor is AKA crank sensor, or if their one same parts that everybody calls differently, or if their two different parts. Do you know answer to this questions? They look the exactly same to each other. haha

[Faja]

From what I've read they are indeed identical, maybe someone else can second that opinion.