I know cold weather really effects vehicles in a negative way so bare with me.

Starting my car in the morning, lets say below freezing, 20 degrees, 10 degrees....

....Start the car up, stays at 1500 for a few seconds then slowly rises to 2000. Now while its at 2000-2100 while warming up, if I "giggle" the stick back and forth in nuetral, the rpms drop to 1500 while I "giggle". If I stop "giggleing" the stick, it goes right back up 2000-2100 rpm's till the fast idle quits in say 15-20 seconds and it starts dropping down...

This ONLY happens when the car is COLD.

Any ideas ??
Remember, im boosted with larger injectors. What could the stick have any bearing on how the car warms up ????

-matt

 

I have that blip in the rpm's when I "giggle" with the gear shift as well, though, not to the extent that you have. Mine might move up and down 100 rpms at most.

 

My car does the same thing. What would make that happen tho?

 

Well the shifter is connected to a switch I believe, which is how manuals can have remote starts without worrying about crashing since it wont start in gear. When this switch is activated is any time when the gear selector is not in the natural neutral position.

I think thats why you get the fluctuation. Matty I believe your problem may be because of the injectors and extra fuel going in. But im not sure.

 

My car does the same thing when it's cold out. I thought it was normal though...

 

I agree - something of the position switch.

They're only $35 and easily replaced on the car.

Dave

 

mine does the same thing, but my mechanic told me its fine.

or probably this position switch would be it.

 

Is this switch you guys speak of inside the trans housing or is it external ??

 

It's the round black one that faces the driver's wheel. People sometimes use it to drain the tranny, but it can be pretty fragile. There is a second piece that rubs against it and is set into the shifter linkage.

Come to think of it, I suggest you *carefully* remove this sensor: alternate prying gently from various sides with a knifeblade and rotating the sensor. (Don't forget the oil drain pan!) The o-ring likes to make it difficult. Wipe the sensor faces clean and wipe off the contact attached to the shifter. (If that contact falls out of the shifter, don't panic - it's just got a couple of pegs that set into holes in the shifter).

Dave

 

you guys also hafta remember that when it is that cold out, the oils and fluids in your car have a lower viscosity. This makes the engine, and drivetrain especially, work harder....so when you start your car and jiggle the shifter, (not "giggle", that's what girls do), you are essentially putting strain on the transmission from pushing the shift forks to the left and right. This would in turn relate to strain on the engine while it is trying to warm up, and therefore cause RPM's to drop. This is normal. As for huge RPM drops, there has to be something else involved. Never, has the engine in my Maxima revved itself to 2000 while being cold out, and I'm from Maine where the mornings are a toasty 20 below. It sounds like you have some multiple problems. Also note that cold weather makes things freeze....like the IACV and such.

 

Moving the shifter from center neutral to either side in neutral will not move the shift forks. If you really want, I have a disassembled transmission, and I could clearly show with photos how the selector moves back and forth without moving the shift rods/forks when you twist the selector from left to center to right neutral.

The only thing in the transmission that notices shifter movement in neutral is that position switch, which feeds back to the ECU, and may therefore affect idle if it's getting goofy info from the sensor.

The IACV is another interesting theory, but again, it would take a wild coincidence for the IACV to stick precisely when he jiggles the shifter in neutral.

Dave

 

Well what I meant by suggesting the IACV, was that his max revs way too high when choking itself out in the cold.

 

You have to remember my car is heavily modded, Lightened flywheel, supercharger, larger injectors, larger MAF....ex, ex, ex. Everytime i change something on my car, the cold start fast idle changes. My pathfinder TB with my 00VI will be going in, this spring, so I expect it to change once again.

 

What position switch do you mean ??


-matt

 

The black one that fits in like a 1-3/4" dia plug on the very bottom of the transmission. It faces the drivers side and is held by one bolt. Some people use it to drain the tranny, but unless you have a replacement I think that's a bad idea. (Removing it from the outside usually cracks it)

 

Thats the Park/Nuetral Switch. Ive replaced that before about 3 years ago

-matt