What spark plug gap are you guys/gals running with the 04+ GTP's?

I'm currently set on .055 with Autolite 104's, headers, 3.6 pulley, PRJ wires and K&N intake. My aeroforce is picking up that it will misfire and I've gotten some sputtering in colder temps at WOT but no KR present during these sputter issues. Is this more ignition coil related or leaning more towards spark plug failure / improper gapping? Could this also be a Throttle issue such as voltage?

I have a feeling that I should be running a tighter gap on the plugs...

_________________

I bought NGK plugs that are pre-gapped, and they work beautifully.

what metal are you gapping?

anything over platinum you run the risk of breaking the electode coming off the porclin if you were to gap them

hence why i run copper 104's at .055

_________________

For comments above, I'm running AL Copper cores.

Looks like my car takes a .053 - .054 gap. The .055 was too big for the pulley I'm running and seems to have limited power, and added random KR under partial throttle (also I misjudged some and I believe a few cylinders were firing with near .056-.057 as well. This went away once I tightened the gap. Misfires are still there, but It is most likely my coil packs, as I have fairly new PRJ wires. The coil packs were never replaced and there is roughly 110k miles on the car.

So, is .053 - .054 what the 04+ GTP's are doing or is my car just odd?

BTW my MAF frequency reading is over 11k as well with just a 3.6 pulley (as mentioned in other threads). Odd eh?

_________________

so stock is .053?

why not try .05?

_________________

What?

"Both of the 2004 Grand Prix's 3.8-liter engines -- supercharged and naturally aspirated -- use the same spark plug gap of 0.060 inches. There is a tolerance of 0.002 inches, meaning the gap may be 0.058 to 0.062 inches.

Source: http://www.ehow.com/info-tip_8739704_sp ... -prix.html

^obviously the above statement is not for AL 104's but where did you get stock is .053?!?

Wouldn't .05 be too little?

Non-intercooled:
3.8” factory: Autolite 605 @ .055-.057” gap (or AP605/APP605 platinums @.060”)
3.4-3.25” pulley: Autolite 104 @ .052-.054” gap
3.1-3.0” pulley: Autolite 103 @ .047-.050” gap
2.9-2.7” pulley: Autolite AR94 (4 range colder race plug) @ .044-.046”

Intercooled
3.25-3.0” pulley: Autolite 104 @ .050-.052”
2.9-2.7” pulley: Autolite 103 @ .046-.048”
2.6-smaller: Autolite AR94 @ .044-.046”

_________________

i just put 104's in the 40th at .050
i run my 103's in my modded motor at about .050 - .055
i dont know what the 97 has in it as the plugs and wires looked new when i put the motor in the car and it ran great so i never bothered.



and yes we know that you said 04+ but the motors are the same but the blower, and some of us have those too. (not me tho)


and the coil packs should be fine right till it quits working. even if it starts getting weak it will be more of a miss then just a slight spark knock.

either back the gap down a touch or try 103's with about .055 and see how it likes that.

_________________

2001 white gt coupe with enough crap to make it run mid 13's with 3 bad pistons
2002 40th GTP sedan mostly stock

Oic, so try .05 instead to try to get rid of misfire?

_________________

well if .055 seems to be too much then try a little less spark. hell no harder than it is to do and no more expensive as they are gap one set at .05 and drive a specific route, then swap in .060 and repete. and see what the car likes better.

_________________

2001 white gt coupe with enough crap to make it run mid 13's with 3 bad pistons
2002 40th GTP sedan mostly stock

My car likes .060 O.o

Sent from my ADR6400L using Tapatalk

_________________

GPDIY - For All Your DIY Needs
VS CAM|3.4|HEADERS|FWI|42.5#|HPT|6000k LOWS|8000k FOGS|

Gapped to .050...seems to like that even better.

_________________

the 99 likes .05 it was having blow out at .055

-- Mon Jan 16, 2012 5:37 pm --



i never trust pre-gapped plugs. does not take long to take out a plug gapper

_________________

92 LeBaron Convert: Turbo 3L 97 Grand Prix GT 4dr "Frankenstein": L67 4t65 swap
97 Grand Marquis: Summer DD 99 Grand Prix GTP: Top Swap Beater