what spark plug should I use ?

[killagt]

I bought some stock motorcraft platium plug, and my intake crack so I think coolant is in spark plug, but now I install a PI intake and some time the car is run not really good, I though it could be spark plug, any ideal ? thanks

1998 gt black 5 speed
PI intake swap.

 

[AaRoN]

are you using the same sparkplugs?

 

[killagt]

Yes I will take a look tomorrow . Is NGK TR55 any good ?

 

[AaRoN]

Yes I will take a look tomorrow . Is NGK TR55 any good ?

yes you are using the same sparkplug? or you don't know?

 

[killagt]

Yes I do using the same spark plug, i think its under 2k miles now, but since that intake crack, car run and idle like crap blow alot smoke too, but after pi intake swap car run better but still light rough at idle.

 

[QTRHRSE]

the TR55 is stock heat range and should work fine.

The TR6 is one heat range colder and would be ok,

TR7 is two stages colder and is WAY to cold for your setup

 

[Pennywise2]

Motorcraft or Autolite spark plugs are the best
choice for a 4.6L in my opnion.

 

[vermilion]

NGK TR55... imo there. your old ones probably fouled out.