When do you guys change spark plugs?

Sonic04GT · Aug 7, 2011

I bought the car with 33k miles on it and it now has 63k. Not sure if the previous owner ever touched them.

Long story short, had a misfire today.

P0316 - Misfire Detected On Startup (First 1000 Revolutions)
P0300 - Random Misfire Detected

Car was shaking at startup but this has happened maybe 3 times over the last couple years. Goes away after I give it a little gas. Never any codes.

Well, today I got some shaking at startup, shrugged it off and maybe a mile up the road I got the Check Engine Light.

I cleared the codes and continued my 3 mile trip and didn't seem to have anymore issues.

I guess it wouldn't be a bad idea to order some spark plugs to have on hand...only $30
http://www.americanmuscle.com/ford-sparkplugs-9904gt.html#customer-reviews

I really hope it's not a coil. I can't afford this and tires right now.

I had the fuel filter changed around 40k miles but Ford recommended replacing it when they did their multi-point inspection during an oil change the other day. Not sure where they got their reasoning for that but I have a filter, just need to put it on.

Could this contribute to the misfire maybe?

darkside03gt · Aug 7, 2011

The missifre wont have anything to do with a clogged fuel filter. At 63k I would have changed the filter about 13k ago. Its a cheap and easy part to replaced, I change mine every other year. I am pretty sure ford recomends it every 30 or 60k but I am not sure.

As far as plugs go I change my plugs every winter along with my blower oil and also clean my air filter. My car usually sees about 3500 miles a year tops, last year it was only 2000 or so.

Deleted member 38176 · Aug 7, 2011

I bought my car with 50K and it now has 70K. I've changed the plugs once (about 65K). I changed them due to a bad misfire. Once changed, the misfire was gone and I haven't had any problems since.

Sonic04GT · Aug 7, 2011

I went ahead and ordered the plugs from AM. I'm going to hold off and see if it happens again any time soon though. In the mean time I need to get that fuel filter put in and clean my air filter.

Green&GoldGT · Aug 7, 2011

I changed mine around 60k miles with Motorcraft replacements. I torqued mine to 30 ft/lbs. I highly recommend these boots also

1999-04 Mustang 4.6L And 5.4L 2V Coil-On-Plug Boot Kit, Black Silicone at LRS - Same Day Shipping!

Sonic04GT · Aug 7, 2011

Green&GoldGT said:
I changed mine around 60k miles with Motorcraft replacements. I torqued mine to 30 ft/lbs. I highly recommend these boots also

1999-04 Mustang 4.6L And 5.4L 2V Coil-On-Plug Boot Kit, Black Silicone at LRS - Same Day Shipping!

I will consider the boots but I can only afford to do mandatory stuff right now, although it would be nice while I have the coils out. Where did you get the torque specs?

darkside03gt · Aug 7, 2011

That TQ spec looks a little high to me. I swore it was closer to 20. 30 just seems to high.

Sonic04GT · Aug 7, 2011

darkside03gt said:
That TQ spec looks a little high to me. I swore it was closer to 20. 30 just seems to high.

Did a little reasearch and I'm coming up with around 13-15

Saw 25 on the 3V's I think.

89lxsport50 · Aug 8, 2011

30 is way to high. I always torque mine to 13 foot pounds with a dab of antisieze on the threads. Make sure you do it on a stone cold engine. Let it sit overnight.

68stang351 · Aug 8, 2011

After having to fix the plug that blew out (yes, I did it myself, never want to do it again) I'm going to leave the rest of them in there until it starts missing. I'm too scared to mess with them anymore. 108k on the car.

Green&GoldGT · Aug 8, 2011

Here's why I said 30 ft/lbs. Quoted right off blownoutsparkplug.com

"Q: Why do you prefer 28-32 foot lbs torque instead of the factory specification?
A: Over the past few years we have heard from many of our customers that they tightened their plugs to the correct torque but they still came loose. We worked with 10 other Ford Certified Master Mechanics and concluded that 28 foot lbs of torque would be satisfactory. We have been using 28 foot lbs of torque for many years and have never had one come loose or strip out. To verify that we would not damage the original threads we used a test cylinder head with good factory threads we applied over 100 foot lbs of torque to the spark plug without any failure."

Stumbaugh · Aug 9, 2011

I change mine after I every 10 bottles of nitrous that are ran thru it.

As far as torquing goes, I get them snug with my fingers, then give them a nudge with the ratchet.

trombonedemon · Aug 9, 2011

Ford recommends to change them at a 100 thousand miles, but I'm not sure if Ford calculated very heavy stop and go driving.

wms004 · Aug 16, 2011

Autolite Coppers every 25k torqued to 16 lbs

Dab a little anti-seize on the plug threads and put some dielectric grease on the top of the plug that contacts the coils.

darkside03gt · Aug 16, 2011

25k on autolite copper core plugs? I wouldnt go past 15k tops.

Jacob_Royer · Aug 17, 2011

I've got a good set of oem cops off an 01 vic I'd let go for $50 if you need them pm me.. I have no use for them

joshjwc9 · Aug 17, 2011

Yeah, if you need boots or COP's go to rockauto. I'm running some OEM branded COP's on my Vortech 2v. Had two go bad off throttle and spent $20 each on the COP's and another $12 for 4 more NGK brand COP boots.

Car is running perfect now...

When do you guys change spark plugs?

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