92SE Auto
86k miles
new Zero miles OEM Nissan transmission installed 3 weeks ago.
All injectors were replaced in 2007 with new OEM parts.

Car will idle between 1500-2000rpm, when put into Drive it will shut off. Starts right back up with the same high idle. Does the same thing consistently. After a few hours of cooling off, it goes back to acting normal without high idle. Very temperamental. Took it to the shop and it is not throwing any codes whatsoever and the issue cannot be replicated.

There is also some rpm dipping and bogging while driving then will randomly shut off sometimes.

Any thoughts or ideas are appreciated.

 

loose/broken vacuum hose or a wire somewhere. with a tranny swap, I'd start looking in that general area for loose stuff.

 

how much did that set you back?

 

Thanks Matt, I'll check that hose. I was also thinking it could be the IAC valve being that its RPM related, and if that's the case, would it throw a code?

I actually paid $800 shipped from a guy who had a new oem VE tranny stashed away in his warehouse for many years in its original Nissan box on a crate.

 

These ECUs really don't throw codes unless it's REALLY bad. I've had all kinds of stuff happen on my engines and never saw a code.

It could be the IACV, but a loose vacuum line anywhere will cause a high idle. Since the IACV is right next to the tranny, that's a good place to start looking.

 

wow sweet deal man 0 mileage VE tranny I would love to see what that feels like one day before I grow old. Are there any downsides to using a tranny that was built many years ago and was just sitting there? Or the box pretty much protects it from any dust or bs.

 

It depends entirely how the thing was stored. you can't keep even a "sealed" engine for a year in Houston weather, but in Arizona you could keep it for several years without corrosion issues.

 

To check IACV functionality, turn the idle screw on it. If the idle changes then it needs replacing. Also, being temperamental, check the coolant flow through the throttle body, IACV and all of the narrow coolant hoses thereabouts, as a blocked one can cause all sorts of issues.

That is of course failing any obvious unattached vacuum hoses or air intake leaks.

 

Thanks for the tip Maxkiller, I'll test the IACV as well as look into the vacuum hose this week when I get a chance. If all else fails, I'll just have to start replacing certain parts and play the trial & error game.

 

Sometimes the small bearings can get distorted (flat spots) from not being moved for so long. It's recommended to rotate the torque converter every now and then, and this will only move some components. Filling the tranny all the way up until it spews out the dipstick tube and vent hose on the top cover is ideal...but you'll have to have little sawed off piece of axle for both sides to plug the hole.

 

Also, did you remove the plenum since the car was working normally? The engine could be hunting, caused by a vacuum leak in the plenum gasket.