Ive been having this problem for a while now so I went out and bought an IACV from JAY25 off of a 98' Engine and cleaned it up good thinking mine was defective....well its not...my car still dropps when Im coming up to a stop and I push the clutch in and let the RPM's drop...they drop to about 600 then rebound and stay at about 1100 till I completely stop then they drop
Why do they keep dropping so low ??
Throttle Position Sensor ??
Maybe my Lightened flywheel is causing this ??

-matt

 

Hummm.... I had the coolant lines that go on the TB bypassed. And had similar idle problems, and when i hooked them up, the idle problem went away.

 

Im thinking its the throttle position sensor thats at fault because I heard on a site it could effect Idle but not likely...Im also have the large problem I cant figure out that may also be the Throttle Position sensor as well...http://forums.maxima.org/showthread.php?t=316304
Bog bog thing when the gas is moved a slight amount and moved back...

anybody ??

 

You are on track with your thinkin. A bad TPS can/will cause all of your probs....have you tested it?

 

I cleaned my TB...Problem went away..Wouldnt a Bad TPS cause CEL to come on?

 

No I havent tested it....my throttle body is clean anyone else ??

-matt

 

Haynes manuel says it could be one of the following,
1) Dirty air filter
2) Vaccum leak (more then likely culpret)
3) EGR valve leaking
4) Fuel pump or fuel injection system malfunctioning
5) Timing chain or sprockets worn
6) Camshaft lopes worn

 

Well I hope its not 5 or 6...

I am mainly trying to figure out the stumbleing thing I am gettin which I explained in other thread...the low idle drop is not really my main concern..I want to know why my car is stumbleing at low RPMS and a shot of gas
Spark plugs
TPS
Comman 5spd problem
clutch hydrolic system is bad

I really need some help on this

-matt

 

Haynes manuel says for engine stumble,
1) Fouled spark plugs
2) Fuel injection malfunction
3) Fuel filter clogged
4) Incorrect ignition timing
5) EGR system malfunction

 

Im going to order some spark plugs tomorrow morning and hope that corrects my Stumbleing problem...its very noticable on the Butt and its very annoying

Thank for all your help

Can you try and find what a faulty TPS would cause ??

-matt

 

Here we go chaper 6 section 8 TPS

The TPS is a variable-resistance potentiometer, mounted on the side of the throttle body & connected to the throttle shaft. By monitoring the output voltage from the TPS, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TPS can cause intermittent bursts of fuel from the injector & an unstable idle because the PCM thinks the throttle is moving. A problem with the TPS or circuit will automatically set a diagnostic trouble code an activate the CEL. On most models, a wide open throttle switch is incorporated into the throttle position sensor. The wide open/closed throttle switch closes the particular throttle circuit in response to the position of the throttle valve (wide open / or closed).

This sounds like it could be your problem due to the information the manuel provides regaurding the unstable idle, but you should deffinitly be getting a CEL if this was the cause of your unstable idle. My bet is the spark plugs should cure your problem. When were they last changed?

 

I changed them at about 90K I think...they cant be more then 40K miles old...my next guess is it may be one of the spark plugs is gapped wrong ??

My idle is fine but maybe the TPS cant react as fast as my foot and give it a spirt too much of gas cause of the throttle position ??

Im really at a loss of guess here...its a stummble in the car thats induced by the gas pedal and the movement of the engine in turn..

-matt

 

if you're running coppers then you should change them every 30k. if you're not, then you should...considering you're boosting now. if you're running plats, they may be causeing a slight detonation problem causeing the car to stumble. are you sure it's not pre-ignition??

 

Whats pre-ignition ??

I am running Nissan platnums

-matt

 

If your boosted s/c t/c nitrous, I don't think you should be running platnum spark plugs. You should be running NGK's 1 or maybe 2 steps colder...

 

I havent put in my S/C yet

-matt