# 97 HB stalling on idle, after reaching temp



## Bannor (May 17, 2012)

Quick background: 236k, owned the truck for last 10yrs/100k miles, mostly stock parts, just changed timing chain myself a couple of years ago.

The symptoms that the truck is having is that once it reaches a stable operating temperature, the engine will idle roughly and often stall. It doesn't surge on normal idle, only when it has been driven for a while.

I checked the OBD code at a local auto parts store, and it came back P0400 - EGR. Looked around the forums and internet. I took off the air filter and holder, and visually inspected components, checked vacuum lines(no hissing heard), electrical connections, etc. I also took apart the main bundle of wires that runs along the top of the engine, with the intention of replacing the poor grounding clamp that grounds several of these intake components. From firewall to components, I found no such clamp.

I ordered a bluetooth OBD reader to use with my android phone, and used it today.

Checked for fault codes, and it returned P0400. It also, however, had a pending (unverified) P0110 - Intake Air Temperature Sensor. I cleared the codes, and drove the truck around for about half an hour before it started acting up again. Right when it suddenly stalled, the check engine light came on again, but curiously the only fault code it reported was P0110.

On starting it back up it died again instantly, and when I kept it running by pushing the gas pedal down a good bit, it sounded like it was missing. Lots of engine shutter, smell of unburnt gas in exhaust, etc.

Addendum: Waited 5 or 10 minutes, started right back up and idles smoothly.

Addendum 2: I forgot to reconnect the IAT to the harness, derp. Thus the new code. Reconnected and cleared. 

After driving it around again, I managed to get some real time information at the moment that the engine began having difficulties:
MAF: Jumped from fairly low numbers to 206.7g/s, and stayed there.
AIT: Was at 50C, not sure where it was before.
Coolant: had reached 78C.
Timing Advance: which was at 11 degrees, suddenly dropped to 4 degrees, and then oscillated between 4, 6, and 8.
Engine Load: jumped to 100% and stayed there.

Suggestions?


----------



## jp2code (Jun 2, 2011)

Are you still getting any codes? If not, yer done!

On the EGR valve, you can buy new ones (expensive), but generally it is enough to clean the old one.

Taking it off requires a really big wrench (like over 26mm) to bust the nut loose from the exhaust manifold.

With it off, spray the insides down with carb cleaner, stick your fingers into the external slots, and work the diaphragm around really good while the solvent eats away that carbon. Squirt that stuff inside the EGR valve, too.

After it dries, you can put it back on. If you put it back on wet, it'll just idle funny for a while.

They also make a MAF cleaner (for that IAT code), but I think that's just electrical contact cleaner. Do not touch the little wire in the MAF Sensor or it can get messed up. Also check the electrical connection going to the MAF Sensor. Sometimes the wires inside there get cracked from that sharp turn they make.


----------



## rogoman (Dec 16, 2004)

A bad idle could be due to a dirty IACV. Easy enough to remove and clean; also check the solenoids attached to it.


----------



## Bannor (May 17, 2012)

Thanks for the suggestions guys, I will give them a go after the weekend, and let you know how it goes.


----------



## Bannor (May 17, 2012)

Just a quick update, I was preparing to tear down the intake and clean it piece by piece, when I found a small, 4-inch piece of vacuum tubing that had rotted out. It connected from the EGR to the pancake thing right above the EGR.

On reconnecting it (and running a bottle of Catalyst Cleaner through the system), it ran much better.

However, after several days of daily use, the behavior has intermittently returned. Sometimes it runs great, other times it chokes and dies. Previously the behavior was constant. So I'm guessing that stuck valve suggestion above is still valid, so I still need to tear down the intake and clean. :|

Could also be the MAF, since the OBD is reporting that code now.


----------



## jp2code (Jun 2, 2011)

The MAF can be cleaned. Sometimes corrosion on the contact plug will cause it to throw.

???


----------



## SPEEDO (Jun 9, 2003)

check that hose (egr to bpt valve) sometimes they get a hole in them, do NOT replace with vacumm hose, it will burn, (oem hose pt# 14755-0F315)


----------



## Shut-Trip (Oct 18, 2012)

*My 1997 Nissan P/up also had a stall- missing problem*

Just for information purposese:

I have a 1997 Nissan P/up Too. had a stall problem, and I called my trusty mechanic and he changed out the dist. cap, and plug wires, and $230 later, problem solve.

Also, Had a bad oil leak thru or around the oil press senor on the oil filter housing. $160 dollars later.. Problem solved.
Plus, the dealer was actually honest, and Fair, in my opinion. (ferman Nissan in Florida)
I usually try to fix problems as far / or as best I can. that way its usually clear what the problem is.
If you have a place to work on the truck yourself, count your self luckier than I. Shunt - trip.


----------

