My hands are bruised, but they are in. It is much smoother now. No reports on MPG, etc. 'cause I just did it yesterday. But even at only 34,000 mi the new plugs made a diffrence. The damn truck had two different plugs in it from the factory. On the driver's side it had a fine point platinum which were eroded quite a bit, and on the pass. side it had a double platinum which were fine. Weird.

I put in NGK TR5-1IX (7243) irridium gapped at .055". These are what is spec'ed for a 2005-2007 4.0 Mustang. If you look up the plug for the SOHC Ranger you get the WRONG PLUG! The reach is not the same. Remember this.

TTYL.

The plug that is correct for the Ranger: NGK TR5-1IX (7243)



The plug that is spec'ed for the Ranger but is incorrect: NGK TR55IX (7164)

 

Good to know, I probably should at least check mine...

 

Really.... Hum.

Idles smoother? IMO mine idles pretty smooth as is.

btw, what does TTYL mean? And.. how did the originals look seeing as you now have a tune.

Rich

 

ttyl = Talk to you later

Thanks for the correct part number. I think every manufacturer has it wrong for the sohc motors.

 

Yea, mine always had a little "bump" at idle. Not quite a miss, didn't hear it out the exhaust, but a bump none the less. Now that is gone. Accelerates a little smoother too. No noticable power gains.

I have used these plugs before (NGK Irridium) and have found the to be worth the money on various applications.


The plugs that came out were nice and clean. Looks like it has a near-perfect mixture and maybe on the lean side if anything. I will not mess with the fuel settings after seeing these unless I can get on a dyno. They look good.

 

Hum.. sounds to me like Ford just did you wrong on the original plugs. My motor is quite smooth. Sometime this summer I'll try a set of bosch +2s and maybe a set of top of the line densos.

Rich

 

Yea, the dude at the engine line must have ran out and just grabbed what fit. LOL

 

Hey, I am going to do that data log soon I promise.

 

thats cool and all, but NGK is for like quads and imports. Motocraft is whats best in a ford.

 

They work fine for me. Just have to get the correct ones. I have nothing against Motorcraft, but where I live I have to go to the stealership and pay out the *** for them. NGKs are available and work well.

 

oh, that sucks cause here motocraft are as easy to get as ngk or anything. Autolite is the same as Motocraft also.

 

I used to only get Motorcraft, but have tired of paying out the *** for them. I know NGK makes their own plug, so the quality is a little better than others. I can get the iridiums for about the price of a copper Motorcraft at the local stealership.

 

Your '04 has an EDIS ignition which uses a "waste spark" design. As such, the spark plugs on one bank see a different polarity than do the plugs on the other bank, and so their electrodes erode differently. Ford has been putting different plugs in opposite banks for years on vehicles equipped with DIS/EDIS.

See: http://www.miracerros.com/mustang/sparkplugs.htm

 

Autolite is still 5144....right?? Cuz, I've swapped my plugs twice now, infact the2nd time was about an hour ago......am I running the wrong plug??

 

Well, I don't know about the different plugs on either side (my Lighting didn't have them though it is coil on plug), but this truck is MUCH better now. It was well worth changing the plugs. Maybe this is because the driver's side plugs (fine tip platinum) were worn so much as compared to the pass. side, and/or the fact that they were all gapped .060 which is about .004 outside of the far side of the specs given on the under-hood decal (I gapped mine to .055), or the iridiums are just that much better. Who knows? I will tell you this: the acceleration is MUCH smoother (no occasional jerkyness), the idle is MUCH smoother, and cruise is MUCH smoother.

I am not pushing this plug, but I have always been pleased with them. They work for this truck, they work for my Lightning with a very cold heat range (idle is smooth, etc.) and when my 'Stang had the long-rod high compression 306, they smoothed the idle with a BIG hyd. roller cam (with the new high comp. HUGE solid roller cammed, stoker motor, they didn't make much difference and during tuning they fouled [fine tip plugs like these foul easier], but I wasn't expecting them to.).

Changing to fresh plugs almost always shows a difference, that is how Splitfire fooled so many people for so long (LOL), but in this case the engine is low miles etc., so I was suprised by how much difference they made.

Go figure...

 

Wow this post saved me a heck of a lot of trouble!! Sorry to awaken the dead, but i pulled my plugs this afternoon after i've been having a lot of stuttering issues at rpm.. turns out the plugs were NGK TR55IX.. Compared to the new plugs i purchased, the reach is completely different!!! I was going to put these back in since they're superior to the plugs i bought, but i definitely wont do that now! lol

Thanks a lot!
Forum prevails again.. whew..

 

Awakening the dead is an under statement for this one.

 

Alot of plug manufacturers STILL haven't updated their lists for 01+ 4.0's in our trucks...they like to call for the old 4.0L OHV plugs for our 4.0 SOHC plugs.

 

i was trying to find those spark plugs last night on the web but i couldnt find the NGK TR5-1IX (7243). where did you get them from?

 

Wow glad I saw this thread. I have 6 of the 7164 plugs sitting on my counter to be put in on Thursday. Big relief. I will have to swap out to the right plugs tomorrow while i am still thinking about it.


BTW not to thread jack but do you guys do wires when you do plugs always? I think I may do wires too but I am not sure. I am at 67k and have not ever done either of the two

 

Also how are you sure that the 7243 is correct?

Link to NGK's website
http://www.ngksparkplugs.com/part_fi...uv/results.asp

Its calling for the 7164 on their site

OHHHHHH whats a guy to do?

 

yea i was wonderin the same im at 67k now too and need tto change plugs should i do wires too neither have been done yet

 

Okay, I am confused after reading this and doing research on my own. I went to Advanceautoparts and put in 2005 Ford Mustang, and they listed NGK 7316 (TR55-1IX) plug for it. I did a search for TR5-1IX and 7243, nothing show up!!!!!

 

It's an easy choice for me.....NGK Irridiums came in my truck from the factory.....

 

If you have a stock engine.. the stock motor craft plugs are a very good choice and value.

If your boosting the stock engine, get a set of denso IT20's.

Rich