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Misfiring after changing spark plugs.

iitsfrost

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So a few days ago, my 98 explorer started struggling at idle. I'll come to a stoplight, and it will dip down to like 500rpm and struggle to stay on. Last night after work, I got 2 misfire codes for cylinders 3 and 6. Today I changed all of my spark plugs and the wires. Cleared all the codes, everything seemed to be fine, as I almost got home. Same misfire codes came back on. How is this possible? Could it be from a vacuum leak somewhere, (which I'm pretty sure my car has).
 



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C420sailor

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Do you have a P0171/P0174 code? Or just the cylinder misfire codes?

Check fuel pressure at the rail.

Check for vacuum leaks anyway. These old girls often have them even when they’re running okay.

If that all checks out, I’d then take a good hard look at the ignition coil pack. Sometimes those crack and get a little wonky.
 






iitsfrost

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Do you have a P0171/P0174 code? Or just the cylinder misfire codes?

Check fuel pressure at the rail.

Check for vacuum leaks anyway. These old girls often have them even when they’re running okay.

If that all checks out, I’d then take a good hard look at the ignition coil pack. Sometimes those crack and get a little wonky.
I've been getting the P1151 code a lot, along with the cylinder misfire codes. I'm going to check my ignition coils in the morning.
 






C420sailor

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When did you last change the upstream oxygen sensors?
 












donalds

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I'm thinking cracked coil pack
 












donalds

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Go outside at night start the truck
Fill I spray bottle with water and mist the engine bay
Look for sparks
This is how I find most bad coils and plug wires ....yes even new ones ...
Little old school but works
 






C420sailor

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Yeah, bad coils don’t like hot engine bays
 


















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Hows it running?
 






iitsfrost

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Hows it running?
Better than ever, my spark old spark plugs were toast anyways. My only issue with the car now is my trans is not gonna last me much longer lol. I just don't have the money to rebuild it. So not sure what I can do about it.
 






EB4X

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Better than ever, my spark old spark plugs were toast anyways. My only issue with the car now is my trans is not gonna last me much longer lol. I just don't have th
I was driving an Aerostar that trans didn't seem it would even last another 48 hours....all kinds of shifting issues....put a bottle of this in and squeezed another 6 months of driving out of it.......and I'm one to shake my head at potential "snake oil" additives....


3010_10009-01-02.jpg
 






iitsfrost

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I was driving an Aerostar that trans didn't seem it would even last another 48 hours....all kinds of shifting issues....put a bottle of this in and squeezed another 6 months of driving out of it.......and I'm one to shake my head at potential "snake oil" additives....


View attachment 341018
So you just put it in the trans fluid fill hole? Like where the dipstick is?
 






C420sailor

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That stuff can help if your trans is just straight up worn out. It basically thickens the fluid, which boosts your pressures.

But if you’ve got broken hard parts in there, it won’t do much
 






iitsfrost

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That stuff can help if your trans is just straight up worn out. It basically thickens the fluid, which boosts your pressures.

But if you’ve got broken hard parts in there, it won’t do much
Yeah last time I changed my fluid which was only about 3 weeks ago. There was nothing in the fluid besides it was just old. It just shifts and acts weird.
 






C420sailor

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If the OD OFF light isn’t flashing, it likely still has some good life left in it.

Hell, mine ate a band and burned up the torque converter and that OD OFF light flashed for 10,000mi before I chose to rebuild it.

Not advisable, but if the alternative is the junkyard....
 






donalds

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Reset your battery after a fluid change
 



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EB4X

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So you just put it in the trans fluid fill hole? Like where the dipstick is?
Yep..... get one of those $8 hand pumps/ siphons to remove same amount of trans fluid of course to make room for this.... and be patient....it's thick like molasses....
 






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