Hi,

I was able to change 5 out of the 6 spark plugs on my 2000 ford explorer and now I have rough idling that drops to 500 RPM and is extremely rough to drive. There is slightly less acceleration than before and when I press the accelerator down far enought there is a loud knocking noise from the engine. please help. I don't want to screw up my car!!

Thanks

 

Are you sure you got all the wires on properly and didn't damage or cross any of them? Also, check for vacuum leaks at the vacuum tree on the drivers side near the firewall. You may have knocked a line off in the changing plugs process.

 

I'm not sure about the 2000 model year but my 1996 requires double platinum plugs because the spark plug fires twice each time. If you used the incorrect or cheaper plug, that would give you problems. Why only 5 plugs? Did you gap the new plugs? You must always re-gap before installing. A crossed wire would be a viable reason for poor performance as well. retrace each wire to the correct plug. If none of this help re-install the old plugs to see if that corrects the problem. On occation, new plugs can be defective or have a cracked insulator. It also sounds like you may be new to wrenching. Did you apply anti-seize on the plug threads?
In any case don't drive it until it is fixed.

 

Acutally with EDIS, the plugs don't fire "twice each time", but they do fire each revolution of the crank, twice as often as with a conventional ignition.
The "double platinum" is needed, because the plugs in opposite banks receive
opposite polarity spark, causing the GND and the center electrodes to erode.

 

If the 6th plug you missed is on the passenger side, try getting to it thru the wheel well.

 

Thanks for the input. I used Bosch regular platinum spark plugs. The plugs I took out looked like single platinums as well. I am going to AutoZone today to hook up their OBDII sensor and check out what's going on. Will it give me the exact problem(S) or just a general answer. Thanks

PS-I also gapped them properly to .054. I also did not apply anti-siezing to the plugs. What will this do? Thanks

 

Not using anti-seize will make it harder to remove the plugs next time.

 

OK got back from AutoZone. The OBD computer said there was a cylinder 2 misfire. Which plug would that be that I need to look at / reinstall. What would be some pronlems associated with a cylinder 2 misfire? Thanks

 

First, with anti-sieze the plugs will never come out again. the dis-similar metals will fuse together. Pull them all and use anti-sieze.

#2 is the middle on the passenger side. Check the wire. You may have damaged it when you were working on it.

Bob,

Are you saying that the spark plug fires on the terminal end of the exhaust stroke. I don't understand how that could be. My understanding was that the plug fires twice, once in each direction(electrode to ground and visa versa) on each compression stroke.

 

If you are going to pull all the plugs out for the anti-seize, you should consider replacing the wires depending on how many miles are on them. Also, why didn't you replace the 6th plug?

 

We are going to go with a plug other than the Bosch Platinums and are also going to replace the wires with some Autolite or comparable ones. The car has a little over 50k miles on it, and so do the wires. The 6th plug wasn't replaced because we ran out of daylight and it looked like a pain to get to, even through the wheel well. Not using anti-seize was my idea, coming from a car-only background, it's use is frowned upon because of how it skews torque wrench performance.

 

Just back off on the torque spec by 3 lbs for the anti-sieze if you use the torque wrench. I simply palm the wratchet and tighten it as snug as I can. I have never had an issue that way and it's hard to get over 10#s of torque. Beside the fact that my torque wrench never fits where the plugs are.

 

Yea, I wasn't able to get a torque wrench on any of the plugs anyways either. Thanks for the help.

 

Yes, they fire 2 plugs together in series, 1&5, 2&6, and 3&4. With one rev of the crank, one plug will be on the compression stroke, while the other is on
the exhaust stroke, and with the next rev of the crank, the first plug will be
on the exhaust stroke, the 2nd plug on the compression stroke. I hope this answers your question.

 

You should use anti-seize, and if anything, it will assure that the plugs are properly torqued!! You should also use plenty of dielectric grease inside the
plug wire boots.....