93 VE automatic. Normal idle in park or neutral between 750-900, correct? Sometimes when I come to a stop I can feel the engine pulling harder than normal while at a stand still. Sure enough, if I put it in neutral the rpm goes to about 1200. It doesn't matter if I tap the throttle, put it in gear and back to neutral, it still idles at 1200. Now if I put it in gear and drive to the next stop light, it may or may not continue idleing high. It idles at normal rpm more so than idling high.

It has always been like that for years, but after being parked for a long time I recently started driving the car again. Many years ago I do remember advancing my ignition timing, so I'll start there. I'll also re-adjust my idle speed. But I am curious, has anyone changed their IAC valve? Why did you change it and did you get good results after changing it?

 

any vacuum leaks?

 

Idle speed is temp dependent - I would start there - check specs on the engine temp sender unit.

If its always done this and you have knowingly changed the timing ............. when is the last time the idle speed was set properly (ECU in set mode and fiddle with the IACV bypass valve screw).

IACV change? - imo its not required - its quite a robust animal, but a good clean-out can/will only do good - the PCV valve coughs up oil/gunk that often get trapped in/on the IACV assembly passages/valve/plunger. If you do strip/clean watch out for the flimsy O-ring used as seal on the actuator motor body

 

chrome91
No vacuum leaks that I'm aware of. In the past couple weeks I've been under the hood for various reasons and I haven't notice (or hear) any vacuum leaks. Besides, wouldn't a vacuum leak cause other adverse effects all the time. Instead of intermittent like mine.

LvR
To be honest, I was thinking somewhere along that line. In the past 15yrs I don't remember ever changing the CTS or IACV. Could it be possible that these components are getting tired, still working but tired. I was asking myself, should I change them just for general purpose.

The idle speed was last checked/adjusted when I advance the timing. It's been so long I can't remember if I was getting irratic idle before or after the timing advance. Good to know the IACV is a robust animal and I'll try the cleaning route.

 

CTS yes, but imo the IACV is super reliable and should never be required to be replaced - sure clean and reset the idling as per FSM, but I wouldn't think spending the beer money on one of those would ever be required (unless you were in an accident that mechanically damaged the IACV housing in some way)

 

Check your battery to ground and alty to ground. I was getting hard start (starter spinning perfectly), starting and stalling, stalling while idling at stop lights, fluctuating idle, temp gauge going up to hot. And all it took was ground strap replacement to fix all that.

 

My VE30DE auto did this exact same thing. It was completely random and would surge up to ~1200rpm, and when stopped with it in D it would feel like its trying to pull away. Turned out it was due to the TPS harness being corroded. The harness was so corroded it wasn't functioning properly. I ended up cutting the harness connector from a parts car in a junk yard, tearing the harness apart, cleaning the crap out of it, putting it back together and wrapping the heck out of it with electrical tape. I had to bend the contact pins inside the harness so when I plugged it on the TPS it made a solid contact.

At this point in time the harnesses are cracked and the contacts can become corroded, green looking. That's what happened to mine.

After I did this the problem completely went away.

I also thought it was my IACV, cleaned the crap out of that and it did nothing. I can't remember if I was having rough starts, too long ago.
Good Luck!

 

Good input, I'll be sure to check the TPS and harness.

 

If you have oil leaks, you might wanna check the pcv valve too.

 

Did you get any hesitation at speed ? My maxima has the idling symptom but also hesitates at highway speed intermittently.