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95 hesitating after changing spark plugs


shlap
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Hi guys, I just changed out the sparkplugs in my 95 pathfinder for no reason other than I knew it was about time (they're at least 15 yrs old). The Pathfinder was running great actually until I replaced the plugs. After that, it was idling a little more rough and hesitating most noticeably when not accelerating.

 

So I took all the plugs back out and checked the gap which I hadn't done before because the guy at O'Rielly told me I shouldn't have to. I'm a novice but trying to be more handy; lesson learned :-). The new ones were all about 28 and my old ones were gaped at 61! From what I've read, they should be about 32 so I gapped them all at 32 and put them back. This helped the rough idle, but it still hesitates a bit (not as much) when cruising along.

 

Given that the old plugs were gapped at 62, should I gap my new ones even more? Or is there something else that I should be focusing on now to make it run smooth again?

 

Thanks!

 

 

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I would check that you didn't break the wires or some random connection in there. Spark Plug Wires, with age, can degrade and fall apart when changing the spark plugs. If you suspect something like that, you can hear a distinctive click when it's arcing to a ground and not making it to the spark plug. It will be most observable when it's dark out and you can see the spark.

 

Mine has a vacuum connection on the back side of the intake that I'm really good at knocking off when I'm messing around in that area, which can cause a rough idle and likely hesitation.

 

Also, If you took the wires off of the distributor cap, it's easy to plug one back into the wrong hole.

Edited by gamellott
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I gapped mine before I put mine in ( lesson learned decades ago with my first car ). I gapped mine to about 36 thou. after I checked their gap. Of the 6 that I bought new the gap was everything from .0315" to .0395. I know that Bosch _claim_ that they spark and resistance test every plug to fit into a specific set of "performance parameters" but I'm calling bull@!*% on that. They may test one of every two hundred or so but I doubt they test every single one.

 

The gap is specific to the spark plug, close the gap and less energy is needed to bridge it ( to get a spark. ) The pathfinder has a serious coil on it so you can run a wider gap if you like. .062 is a bit much in my opinion. I wouldn't hesitate to run the gap at .0450" though. I suspect your hesitation _may_ be due to the smaller gap and not enough time to get a complete burn of all of the fuel in the cylinder but there could be a hundred more reasons having nothing to do with what's going on in the cylinder for that to happen!

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Thanks guys!

 

gamellott -- I did have to replace the vacuum hose as it crumbled the second I touched it, hah! :-) There's nothing I need to do other than put a new hose back on right? I tried not to touch the plug wires much and didn't unplug them from the cap.

 

SpecialWarr -- being how it was running smooth before the spark plug change, I have to assume it's the plugs or the wires.

 

I guess I'll try gaping them all to a slightly larger size, maybe .45 and see how she runs. If that doesn't work, I guess I'll have to buy new wires and see if that helps.

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Replacing the hose should be all you need to do for that. Just be aware that there are likely many more in the same condition as that one. You could probably spend an afternoon re-plumbing the hoses with 10' of hose and still miss one or two.

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LOL it could be a whole lot worse. I've seen schematics for smog-era carburetor setups that look like the maze on the back of a kids' menu.

 

Replacing the vac lines shouldn't take too long provided you don't break anything. Just do one line at a time so you don't get them crossed up. The only tricky one is the one to the fuel pressure regulator behind the intake, that one's a braille job. And there should be a sticker on the underside of the hood with the vacuum routing all laid out for reference. I don't remember for sure how much line I bought but I don't think it was more than 6' (and I bought extra because it's cheap and it doesn't stretch well).

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What plugs did you use? I only use the ngk V power copper plugs. There is no difference at all with the other fancy ones and autolite/bosch are garbage.

 

My friend's pathy had a gap of .080" and it still ran very well lol. This just proves that there is no need for BS msd ignition crap on these vehicles.

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What plugs did you use? I only use the ngk V power copper plugs. There is no difference at all with the other fancy ones and autolite/bosch are garbage.

 

My friend's pathy had a gap of .080" and it still ran very well lol. This just proves that there is no need for BS msd ignition crap on these vehicles.

 

I used Champion plugs.

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  • 1 month later...

I also recommend NGK. Nissan suggests a hotter plug then the #6 that the auto stores will sell you. I had new sixes and replaced with gives and the hotter pug solved several issues.

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Please put NGK plugs back in. If you are still having issues after doing that, finish the tune up. Cap, rotor, wires at a minimum. You said the plugs were 15 years old, I'm assuming the rest is at least that old.

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I also recommend NGK. Nissan suggests a hotter plug then the #6 that the auto stores will sell you. I had new sixes and replaced with gives and the hotter pug solved several issues.

 

Really? I have always run the BKR6EY plug and have never had any issues. Truck runs great, with good mileage for what it is.

 

Theoretically ANY plug that is the right heat range will work fine, for example the garage that installed my new engine in my Xterra, used Delco plugs. It runs great, so I'll leave it, but NGK is what Nissan calls for and what it will work best with.

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Oh I love the network I'm on!! Retyping this again....

 

I believe Champion plugs are OEM on Chrysler products. You're always better off with "Like" material/products. There are slight variances in production between manufacturers that MAY cause performance issues. Nissan puts NGK spark plugs in their vehicles and you'll get better consistency/longevity out of the OEM ignition parts than most other variants. In Theory, Yes, they should work fine. In reality, they don't always work that well.

 

Kinda along the lines of using GL5 gear oil in the transmission in this vintage vehicle. In theory, you can use it. In reality, it's not a wise idea. But that's a whole different discussion ;)

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I dunno if spark plug selection is as dire as a transmission oil that eats synchros, but sticking with what the engine was designed with is a good general rule. When I bought new plugs for my rig, I got NGKs.

 

Near as I can tell, they run exactly the same as the Autolites I took out.

 

Maybe it's more a matter of a quality plug than NGK having the eleven secret herbs and spices that Nissans require. I haven't read many accounts of people being happy with Champions.

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The only thing I use champion plugs for is to break into pieces so I have a piece of ceramic to throw through the window of any A-hole who leaves their dog locked in a hot car.

 

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