Running with a Slight Sputter?

[yonyon]

Originally Posted By: Gebo

It's a stumbling surging bog combination under somewhat less than "petal to the metal" acceleration that is most pronounced on a 34 degree upslope between 2000-3100 RPM's.

That's a rough one. Assuming it's okay under hard acceleration and higher RPM it shouldn't be the distributor bushing or pooped coil insulation.... maybe a dead spot in the TPS? Does it smooth out if you wiggle the accelerator pedal? Wait, that I'm making an assumption for no reason. How is it under harder acceleration and higher RPMs? How about just higher RPMs if you downshift?

 

[OVERKILL]

Originally Posted By: yonyon
Originally Posted By: Gebo

It's a stumbling surging bog combination under somewhat less than "petal to the metal" acceleration that is most pronounced on a 34 degree upslope between 2000-3100 RPM's.

That's a rough one. Assuming it's okay under hard acceleration and higher RPM it shouldn't be the distributor bushing or pooped coil insulation.... maybe a dead spot in the TPS? Does it smooth out if you wiggle the accelerator pedal? Wait, that I'm making an assumption for no reason. How is it under harder acceleration and higher RPMs?


I know when I had a failing coil in my 5.4L (it has COP), it would only act up in the exact scenario the OP is depicting. It was a misfire on #7 cylinder that only appeared under low to medium RPM at high loads. If I got on the throttle enough to trigger a downshift, it wouldn't do it. The RPM's had to be low (relatively) and the load high. It was fine at WOT.

My misfire showed up as a pronounced buck or chug which is how I'm envisioning what the OP is describing. This is also part of why I'm advising he put the right plugs in it to start. The more variables we eliminate (the right plugs, at the proper gap) the easier it is going to be to figure out this problem.

 

[Trav]

He apparently has 3 confirmed issues.
Wrong heat range plugs
An EGR code
A defective vacuum hose to the EGR

IMO its probably better to get the known issues out of the way then see where this leaves it and go from there.
I hate to see the cart getting in front of the horse.

It could be a bad vacuum advance (if it uses one), rotor, dist bushings, wires, etc but opening too many cans at once is going to get confusing.

 

[OVERKILL]

Originally Posted By: Trav
He apparently has 3 confirmed issues.
Wrong heat range plugs
An EGR code
A defective vacuum hose to the EGR

IMO its probably better to get the known issues out of the way then see where this leaves it and go from there.
I hate to see the cart getting in front of the horse.

It could be a bad vacuum advance (if it uses one), rotor, dist bushings, wires, etc but opening too many cans at once is going to get confusing.

Exactly my thinking Trav

 

[ARCOgraphite]

overkill 5 are still HOT on the heatrange scale and are confirmed smog plugs that have detonation issue with low octane lstioc running. Ive tuned many of there engines and none need a 5 NGK STD Nickel plug. Now Ive found in tuning that the Ir 5 heatrange is a wide range plug and works wherte 6 works where 5 worked in the past as it has a lower voltage spark threshold. Nissan usually stated in the OM and engine service manual that you can run a #6 for performance use - even noted in the light pickup truck manuals (4 cyls) of this era.

 

[OVERKILL]

Originally Posted By: ARCOgraphite
overkill 5 are still HOT on the heatrange scale and are confirmed smog plugs that have detonation issue with low octane lstioc running.


Yes, they are relatively hot, and that is partly for emissions of course. But they are the appropriate plug for the application. It is pretty easy to check a plug for signs of detonation as I'm sure you are familiar with the process.

Quote:
Ive tuned many of there engines and none need a 5 NGK STD Nickel plug. Now Ive found in tuning that the Ir 5 heatrange is a wide range plug and works wherte 6 works where 5 worked in the past as it has a lower voltage spark threshold. Nissan usually stated in the OM and engine service manual that you can run a #6 for performance use - even noted in the light pickup truck manuals (4 cyls) of this era.


In that vein, a truck is going to be a more demanding application, resulting in higher cylinder temps and working the engine harder, so I could see why Nissan would list the colder range plug as an option there. However, we are talking about a Sentra here.

BTW, my Expedition plugs are an NGK "5" heat range

FWIW

 

[Gebo]

My EGR rubber tube and the rubber rocker gasket should be in tomorrow. I'll be changing plugs Thursday if the sun shines.

I could tell no difference at all in my engine's response with the EGR rubber hose removed. All I got is a CEL that stays on all the time. I'll check it out tomorrow and verify it is still code 32.

I have noticed it does run better before the engine warms up. I was thinking as I was on my way to work this morning, I believe I'll just leave the EGR hose off if it runs this good. But then in about 3 miles the same issue started back up. That made me wonder about the "hot" plugs. We'll soon find out. If the plugs don't do it, I'll probably head out and buy a coil.

Thanks for all your help.

 

[Trav]

If the EGR hose was leaking and you just pulled it off it wont make any difference, it still has a vacuum leak.

Did you plug the port where the EGR connect to the engine?
A piece of hose with a golf tee or small bolt stuck in it will work okay.

 

[The_Eric]

Originally Posted By: OVERK1LL

Eric:

Respectfully, I don't have it backwards, please read through the thread again.

He hasn't taken the 4's out yet, they are still in the engine. Those are the plugs I am referring to as too hot.

The OE plugs, which are the ones he put in and then the mechanic took out when the owner he bought the car from had it serviced, were 5's, and he (the mechanic) replaced them with the 4's.
-Chris


Yes, I think I may have had a bit of "reading comprehension failure"...

 

[OVERKILL]

Originally Posted By: The_Eric
Originally Posted By: OVERK1LL

Eric:

Respectfully, I don't have it backwards, please read through the thread again.

He hasn't taken the 4's out yet, they are still in the engine. Those are the plugs I am referring to as too hot.

The OE plugs, which are the ones he put in and then the mechanic took out when the owner he bought the car from had it serviced, were 5's, and he (the mechanic) replaced them with the 4's.
-Chris


Yes, I think I may have had a bit of "reading comprehension failure"...


Happens to the best of us, no worries

 

[Gebo]

I replaced coil but didn't change plugs yet. I'm trying to learn as i go through this "experiment." Good news...the hesitation is fixed. I went from 35 mpg on my first 2 tanks. My 3rd tank was 40 mpg with EGR tube removed but coil was replaced. My last tank was 31 mpg with nothing done to engine. Maybe I messed up when i filled up because the 40 mpg tank was done at a full service station and he didn't get it completely filled???


Here's what we have going on now. As I wind it up from 1000 rpms to say 4000 rpms going through the gears it will sporadically ""burp" like it just had a big miss. It's almost like you jerked your foot off accelerator for 1/10 of a millisecond. It is not repeatable. Now for further information, I drive to work on a regular route and there is one "extended" hill. Close to 1/2 a mile steady incline. I was so happy yesterday as I was going up this hill yesterday and didn't have to downshift. I said it out to my wife, "Hey, we are not losing any speed!" Well, today going up the same hill, I had to downshift and still lost speed. Is it possible with this little 1.6 engine the AC could pull that much drain on the HP? It just occurred to me coming back from church today so I'll do further investigation this week.

I believe the loss of power and the "burp" going through the RPM range are somehow related. I'll now more about gas mileage as I get through this tank. If unplugging the EGR tube gets me 5 more MPG, I think you know what I'm gonna do.