F150 Ecoboost Forum banner

61 - 68 of 68 Posts

·
Registered
Joined
·
1,695 Posts
Watch out for the 542 replacements “578’s”. They are hotter plug and not iradium. I tried the 578’s just for fun and lost 2* of timing. Not good.


Sent from my iPhone using Tapatalk
I was reading on another forum some are reporting the same thing...... 580's and 550's are starting to get a lot of talk going... I am going to grab 4 more sets and I should be good for a few years!!
 

·
Registered
Joined
·
3,557 Posts
I swear gearhead used to ship pre-gapped 542’s for the gen 1 3.5. I was trying to confirm but I cannot find the receipt for my order. I def got the plugs with my tune though and I wrote down SP-542’s on my maintenance log.
 

·
Registered
Joined
·
280 Posts
I swear gearhead used to ship pre-gapped 542’s for the gen 1 3.5. I was trying to confirm but I cannot find the receipt for my order. I def got the plugs with my tune though and I wrote down SP-542’s on my maintenance log.
Them, Unleashed and MPT all have the 542's as "the" plug. I looked at GH's site last night but couldn't find any plugs, but I remember seeing them there before they did a website change.
 

·
Registered
Joined
·
1,290 Posts
I swear gearhead used to ship pre-gapped 542’s for the gen 1 3.5. I was trying to confirm but I cannot find the receipt for my order. I def got the plugs with my tune though and I wrote down SP-542’s on my maintenance log.
I remember it too. Pretty sure Matt recommended and sold the 542s. So what plug should we use now for the same heat range? Is there any step colder?

To be fair, I have used a mix of OEM or NGKs and have had ZERO issues. Even using the copper accel plugs in stock heat range and one step colder were fine for me.
 

·
Premium Member
Joined
·
4,893 Posts
I swear gearhead used to ship pre-gapped 542’s for the gen 1 3.5. I was trying to confirm but I cannot find the receipt for my order. I def got the plugs with my tune though and I wrote down SP-542’s on my maintenance log.
I've been in the office that had bookcase shelves of them stacked. Watched them pre-gap a set for me.

I wonder if they ran out of them as they are being superceded?

I'm due for a set at 25,000 miles.



Sent from my SM-N950U using Tapatalk
 

·
Registered
Joined
·
3,557 Posts
I've been in the office that had bookcase shelves of them stacked. Watched them pre-gap a set for me.

I wonder if they ran out of them as they are being superceded?

I'm due for a set at 25,000 miles.



Sent from my SM-N950U using Tapatalk
Or they ran out of people to gap them once they became popular lol. I ordered my tune pretty early on I think.
 

·
Registered
Joined
·
58 Posts
curious as to what others are saying about the 578's, i put them in my truck and it just seems a little hesitant and especially on start up, it's not anything bad or noticeable to another driver but to me it just seems a tad bit sluggish on take off, so yeah i would like to hear some of the feedback, i just got a set of 580's and before i change them i would like to make sure i'm not crazy
 
61 - 68 of 68 Posts
Top