So I put in some NGK LRT5IX-11 4344 plugs and they are gapped at 42 talked to the tech's to verify gap they suggested keeping them small for performance. So I dropped them in fired right up and rev it to like 3K and on the rev down you can here a pop not like a gun shot backfire but still not a normal sound. Do you think the gap is too small or plug could be bad or something else? I am waiting on it too cool down and put stock plugs back in and see what it does.

Thanks in advance,
BigB

if your car is still naturally aspirated, you should be running a .052-.056 gap. .042 is way too small for naturally aspirated, at least on this generation ford engine

Thanks for the quick reply... let me go regap them and I will let you all know how it goes.

BigB

also, a certain amount of popping from the exhaust is normal. I don't recall what the actual reason for it is, but I know that it's pretty normal

Ok, got them gapped to .052mm and now only one pop only if I take it to 2K and let off.

Should I be worried, should I just drive it a see how it goes?

Concerned,
BigB

I wouldn't be too worried. It's a normal sound.

my exhaust pops... I love that sound actually... makes me feel tough... well, as tough as a stock motor focus can get...

kinda reminded me of the neon srt-4 exhaust sounds...

I felt so powerful when I first heard my exhaust pop. It was the first night I took her out to the mountain trails with my SE-R buddies. Ahh... the memories.

Yeah, I liked the popping too but that went away with Waynes tune ..... but hey, it's a fair trade LOL

I've actually researched the popping...the cause is...SPARK TIMING!!!

when you let off the gas, whether you're in gear or not, the computer automatically pulls the spark timing back down to 8-10 degrees BTDC. at higher rpms, under load, the spark timing is advanced because there isn't as much time for the air/fuel mixture to burn. if the engine is still at those higher rpms, and the spark timing reverts to base timing, the exhaust valve is opening before the air/fuel mixture burns completely, allowing the still burning gasses into the exhaust system. this is what causes the popping sound. a more radical form of this can be seen on rally cars that employ a "bang-bang" system to keep the turbo spooled

^^^ Hmmmm, that makes me wonder if that could be part or all of the reason our cars tend to bog so much down low when we try to take off with the spark timing changing so much. Is it possible?

Wow, that is cool linfo...

Well, so far have not driven my car much but I have not been hearing it while I dive just when I was parked the first time I intalled them and then had to adjust the gap larger...

As for driving seems really smooth yes could be just having the new plugs no matter what brand would have given such results. only have 11K on the car so far...

: )