# 96 HB missing at high RPM, dying at idle



## tomato soup (Sep 26, 2010)

Hi guys, sorry for making a post in the general truck forum, but I didn't realize there was a separate Pickup forum.

So, I've seen this problem described multiple times by other people all over the internet, but there have also been as many different answers so I don't know where to start.

Last week my truck started skipping or missing at around 2500 rpm on the interstate, which freaked me out so I slowed way down and pulled off at the first exit I came to. While at the red light, my truck completely died while idling extremely slowly. I put it in park and restarted, it was still idling slowly but would run fine up until around 2500 rpm. Since then the problem has repeated several times.

November 2011 I had the distributor and cap replaced, so I immediately got a replacement distributor (but not a cap) under warranty from the parts store and the truck ran completely fine for a day. No skips at high rpm, no low idle speeds and no dying at prolonged stops. But the it started acting up again the next day...

At this point I have visually inspected connections and nothing seems obviously out of place or disconnected. Unplugged the MAF sensor (I think) and the problem was worse. This is not a consistent problem, sometimes it happens from a cold start but this morning it was idling at normal speed and I could rev it up to 3k with no issues.

I need some ideas... You all helped me replace my starter a year ago and it was one of the best feelings ever having triumphed over such a complex machine. I wanna do it again, guys.


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## smj999smj (Jan 1, 2006)

Check for a sticking EGR valve; Nissan has some issues with them on the 96 models,


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## tomato soup (Sep 26, 2010)

Oh snap, smj999smj I think you helped me replace my starter...

Anyway I looked up the Exhaust Gas Recirculation valve and what it does. Am I right in thinking that sticking open would slow my spark timing and sticking closed would increase it? Regardless, how would I go about checking it? I'm familiar with the inside of my truck but I don't know proper terms for things.

Thanks


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## smj999smj (Jan 1, 2006)

The EGR valve is used to divert inert exhaust gas into the intake manifold under certain conditions to help control combustion chamber temperatures and reduce NOx emissions. If it sticks open at idle, it will cause the engine to run rough and likely stall. It's located at the back of the intake manifold and is in a real pain in the butt location, if you have to replace it. It can be tested using a vacuum pump to manually apply and remove vacuum to the EGR diaphragm. Nissan issued a TSB for 96 HB's in regards to this and advised to replace with a countermeasure EGR valve.


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## tomato soup (Sep 26, 2010)

Thanks for the explanation, but would this also relate to the 2500 rpm limit I'm experiencing? It seems like it would, but I want to be sure because I wanna have a list of likely things for the mechanic to check first on Monday.


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## smj999smj (Jan 1, 2006)

Is it misfiring at 2500RPM or is it "surging" and being limited to approx. 2500RPM? I ask because 2500RPM is what the engine is limited to in "fail-safe" mode. If that's the case, check for stored trouble codes.


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## tomato soup (Sep 26, 2010)

Hmm, I guess I'm not sure what exactly "surging" is, but what I'm talking about feels like the brake is being slammed (along with what sounds like no firing) while I'm trying to drive causing the truck to buck pretty damn hard at high speeds. 

Would surging be if the engine just wasn't revving above 2500, and would build up then drop rpm at the same point? Because that's not quite what this feels like.


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## zanegrey (Dec 5, 2005)

READ THE CODES AND TELL US THE MILEAGE..


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## tomato soup (Sep 26, 2010)

How do I read the codes? 

I have 217500 miles on it, owned it since 2004.


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## smj999smj (Jan 1, 2006)

Any auto parts store can read the codes being that it is OBD II compliant and will usually do so for no cost. Or, you can do it yourself and get the manufacturer's codes via the ECM. I believe there's a "sticky" at the beginning of the HB section on how to do this, or go to www.troublecodes.net/Nissan


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## zanegrey (Dec 5, 2005)

WHAT DO YOU KNOW ABOUT THE TIMING CHAIN ??


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## tomato soup (Sep 26, 2010)

Ok, I will get any error codes from an auto parts store tomorrow and post them here (and check them myself). My check engine light isn't on though, will it still show error codes?

Also, only thing I know about the timing chain is that it hasn't been touched since I've had the truck.


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## tomato soup (Sep 26, 2010)

So, I have now dropped my truck off with the mechanic. I gave him a list of likely things to check first, and will let you guys know what he thinks.

Again, as my check engine light is not staying on I have no error codes to report.

Please keep this thread in mind as I will be posting everything the mechanic suggests and does, along with what finally fixes the problem (hopefully).

Thanks for help so far.


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## zanegrey (Dec 5, 2005)

FORGET THE CEL.. READ THE ECM CODES..

IS THE TIMING CHAIN MAKING NOISE AS YOU START THE ENGINE AND SHUTTING IT OFF..?


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## tomato soup (Sep 26, 2010)

well I went to the auto parts store and the code reader didn't show anything... the lady said the check engine light had to be on to get error codes

what sort of noise would a timing chain make? because i'm not noticing any new weird noises


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## zanegrey (Dec 5, 2005)

read the sticky and read the codes...


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## tomato soup (Sep 26, 2010)

Ok, well I don't wanna be a dick but the sticky is for 95 and older models... Please at least read what is going on before making comments.

Thanks bro.


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## zanegrey (Dec 5, 2005)

ok dick.. it can be read the same way.. pm me your email address and i'll send you the 96 pdf..look in the ec section..

yw dick....


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## tomato soup (Sep 26, 2010)

well anyway, I don't have the truck atm... it is now at the mechanic's shop. 

can you post direct download link for pdf?


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## tomato soup (Sep 26, 2010)

I am getting my truck back from the mechanic today. He has told me he thinks the rebuilt distributors have been faulty and to try one from a different parts manufacturer. He also suggested a diagnostics garage which could do more in-depth tests if it's not the distributor.

I will attempt to read any error codes this week while I've got it at home.


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## zanegrey (Dec 5, 2005)

UPDATE......


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## tomato soup (Sep 26, 2010)

I think I'm going to take it to the diagnostic garage on Tuesday and hopefully have it back by this next weekend... I haven't had time to figure out how to read the codes myself but if they don't at the shop then I'm still going to try to do it.

idk what else to do at this point. I don't want my truck sitting at a garage but this problem seems WAY over my head.


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## tomato soup (Sep 26, 2010)

Just heard back from the diagnostics shop... MAF sensor and bad distributor. Confirmed that no codes were showing up. They want 617 dollars to replace just the MAF sensor.

Is the part only around 200 bucks? Because I'd rather have my mechanic do the labor and not charge me 400 dollars for it.


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## zanegrey (Dec 5, 2005)

u can call ur local nissan parts counter and ask how much for that maf.. ( but it is probably more than 200 dollars..) there are only a few screws that hold the maf on so i doubt that they are charging that amount to put it on..

imo.. if the ecm did not show any codes for those parts then they are not bad...

again this is my opinion .. audience of one..


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