2002 Nissan Sentra Idle Problem PLZ help!!!!!

[davidpark9677]

Hi everyone, this is my second post based upon "huge Idle Problem" right below couple days ago. I have ran in to couple problems just about couple weeks ago regarding idling. Since than, I couldn't figure out what the problem was, so took it to the shop and did a diagnostics. I've finally paid for 90 dollars to do the diagnostics. Well after diagnostics, the shop told me it needs a new cam sensor, crank sensor, EGR valves, and new set of spark plugs. I've went ahead replaced all of them by myself and did a relean idle. Well here's the problem. First of all, at 1500 RPM, it jumps like a rabbit. engines constantly going up and down from 1500 to 2000. When I am driving, if I let the gas go, when it reaches around 1500RPM, than it jumps up to 2000 and slowly comes down. The idle problem while it's at stop has gotten whole lot better, but it revs at higher RPM and it jumps!!!Does anybody ever had this type of experience? by the way my spark plugs gets burn real quick. I used iridum spark plugs btw. Somebody please help!!!!!!!!!!!!!!!!!!!!!!!!!!!!

BTW when I was doing idle relearn, I've done it with my dad holding stop watch, and the MIL light never came on solid. It just blinked for like 10 minutes. Any solutions?

[wanner85]

Im no Nissan expert but it seems you got robbed. I find it hard to believe you needed a cam and crank sensor, and an egr. For 90 bucks you can get a generic OBD2 scanner and diagnose check engine lights (MIL) yourself. Also, not sure about the idle "relearn" but most cars will have to go through a drive cycle before they become "self aware". And, a blinking MIL usually means an unusually bad misfire.

[spec_v03]

first off, you shouldnt have to take it to a shop for diagnostic, you can self diagnose with no tools whatsoever. if you want i can link you a write up, but its basically just the last part of the idle relearn, when the MIL light blinks, its blinking out the code.as for your problem, shoot a quick video of the tach when the idle acts up. are your spark plugs gapped correctly? should be ~.044. are there any vacuum leaks form the hoses to the intake manifold, TB, or intake itself? try spraying soapy water on the lines and look for bubbles, if there are any, theres a leak there.

[spec_v03]

also, what trim/motor is your sentra?

[davidpark9677]

Thanks for the reply, It's a 2002 Nissan Sentra GXE model. I think it's 2.0 liter engine I am not sure if it's 1.8 or 2.0 right now. I've been working on my other car for lately. BTW, there's no leak, I've double checked it. Sparkplugs gaps are correct. I was told that my EGR Valves and EGR valve temp sensor needs to be replaced with EGR valve gaskets, Plenum gaskets, intake gaskets, manifold gaskets, throttle body gaskets. I seriously ain't got a clue on this car. There is no vacumn leak, nor oil leak. It's keep showing the code as coil/secondary manifold misfiring, but if it's coil that's gone bad, they usually show up which cylinder that needs to be replaced, but it's not even showing that. It doesn't idle when it's at any mode, but whenever RPM hits 1500 it goes up and down up to 2000. whenever I rev, the RPM tachometer feels little to slow when it's coming down. it seems like it's holding it up and coming down very slowly. Any help or any advice can be greatful. As I am willing to work on this car tomorrow all day.

[djtorello]

Id take a look at your Idle Air Control Valve, and look for a vacuum leak.

[nametakennow]

Blinking MIL = Get it to a shop. Don't keep driving it til you do. When it's blinking, there's a definite risk of damage.

[davidpark9677]

Id take a look at your Idle Air Control Valve, and look for a vacuum leak.

Yesterday, I have worked on this car all day. I've taken off, air intake, throttle body, IAC valves, EGR vavles, intake manifold. I was hoping that it would be a intake manifold gasket leak, but it wasn't. I've cleaned out real good with degreaser, carburator cleaner, and etc. once I have done finishing what I was doing, I started car back up, still the same problem. even replacing EGR valve temp sensor. btw, I have replaced plenum gaskets, EGR valve gaskets. have any other Ideas? I have ran out of mine. T.T

BTW, I've researched on blinking MIL lights, and findout that it's constantly misfiring cylinder problem.

[bassmek2]

if it is comming up as coil it could deffenatly be the number one coil the power transister is bad possibly this would cause an idle issue cause there is no signal being sent back to the ecu other causes are crank/cam postion sensors or short in one of the wires that lead to these sensors oh and the variable valve timing sensor

[PapaSmurf2k3]

try spraying soapy water on the lines and look for bubbles, if there are any, theres a leak there.

That doesn't really work with vacuum leaks... only with pressurized leaks (like a leaky tire). The bubbles are caused by escaping air, but vacuum is sucking the air in, not pushing it out.

OP: I'd try and get your $90 back from the diagnostic guys, they were obviously wrong. If everything they said was wrong was actually wrong, your car wouldn't even start.

[bassmek2]

yea definatly not soapy water if u want to check for a vacuum leak spray some carburator cleaner around the intake where its attached to the head and everywhere else there is a gasket on the intake..then check hoses and just put your ear there to listen for the leak (hissing sound)...