air leak after sparkplug change/ bad idle

[anyo91]

hey guys,
i changed my plugs yesterday and after i got everything back together i noticed a fairly loud air leak sound comming from my plenum, after the plug change my car has been idling horrable (like bouncing between 500 and 1k rpm, but not all the time, it comes and goes, and the engine vibrates more than usual too) also i have a loss of power.. and my check engine light came on and the code was p0302, misfire cylinder #2. I thought the plenum gasket was bad so today i pulled everything back apart and replaced the gasket with a new one, but no luck it still has the same exact problems. does anyone know what could be going on? this has been driving me crazy! its a 03 with the v6.

thanks in advance,
Cody

[tamim13]

If it was just after changing the spark plugs, it might be just the spark plugs. What plugs did you put in them? Put back the old plugs and see if it still happens. Did you forget to connect the wires properly?

[anyo91]

i replaced the plugs with NGK platinums and carquest wires. and all of the connections are seated properly, i checked last night when i took it back apart. ill try putting in the old plugs (if i didnt throw em away, i cant remember if i did or not)

[tamim13]

Why did you change the plugs and wires? Were there any symptoms before you did it? Also put back the old wires and check. You did not replace the coil backs, did you?

[anyo91]

i replaced the plugs and wires because i just hit 100k miles and wasnt getting the best mpg. but i didnt have any problems before changing them. and nope i didnt replace the coil packs

[P'NOYcaL]

i just change my spark plugs yesterday too since i have 130k miles on mine i never had problem. I took my time replacing them one at a time.
Make sure:
1.) You measure the new spark plugs gap apprx. 0.39 - 0.43 (VERY IMPORTANT)
2.) Clean every cylinder where the plugs sits in, clean the rubber boots, and dust every wiring.
3.) It's also a good idea to lightly coat the threads of the new plugs with anti-seize compound.
4.) Proper tightening/torque about 25lbs (i would say average arm tight) is also critical making sure they sit properly to get the proper equal combustion on every cylinder.
5.) Voila! Enjoy the additional 10hp on your car! lol (if you insist)

[galantlvr34]

i just change my spark plugs yesterday too since i have 130k miles on mine i never had problem. I took my time replacing them one at a time.
Make sure:
1.) You measure the new spark plugs gap apprx. 0.39 - 0.43 (VERY IMPORTANT)
2.) Clean every cylinder where the plugs sits in, clean the rubber boots, and dust every wiring.
3.) It's also a good idea to lightly coat the threads of the new plugs with anti-seize compound.
4.) Proper tightening/torque about 25lbs (i would say average arm tight) is also critical making sure they sit properly to get the proper equal combustion on every cylinder.
5.) Voila! Enjoy the additional 10hp on your car! lol (if you insist)

you can't gap platinum plugs.and you dont want to over tighten the plugs so just tighten them until they are snug.

[P'NOYcaL]

Don't tell me i wasn't suppose to gap the OEM mitsu plugs(i believe they are platinum)

was i suppose to just leave them as they are?
Although I never had problems..

As far as what i've read somewhere in this forums (and there was couple of them here) they said the recommended gap is between 0.39-0.43
And when I got my spark plugs they're gapped around .50+(which is way far from the recommended gap) so i figured i could do some adjustment.

[M-Rod]

I would check the hard vacuum lines on the back of the plenum and make sure none of them are disconnected at the ends. Better yet, check all vacuum lines going to the solenoids and throttle body. Changing the spark plugs wouldn't cause any issue, despite what anybody else is saying, since the V6 and I4 are completely different. It sounds to me like you just have a vacuum leak.

[galantlvr34]

Don't tell me i wasn't suppose to gap the OEM mitsu plugs(i believe they are platinum)

was i suppose to just leave them as they are?
Although I never had problems..

As far as what i've read somewhere in this forums (and there was couple of them here) they said the recommended gap is between 0.39-0.43
And when I got my spark plugs they're gapped around .50+(which is way far from the recommended gap) so i figured i could do some adjustment.

the oem ngk plugs are not platinum.as long as it doesnt say platinum then the plugs can be gapped.

[galantlvr34]

yeah it deffinantly sounds like a vacuum leak,do you hear like a hissing type of sound?like m-rod said changing the plugs wouldnt cause a bad idle.

[anyo91]

I'm stumped, I've checked all the vacuum lines... Nothing and the sound is comming out of the front left side of the plenum right next to the cylinder 2 injector. Im taking it to my mechanic today... Ill let you guys know how it goes. Also the plugs were pre tapped at .039 but I checked everyone of em before installing.. Also I've never actually been told why you cant gap platinum plugs.. I know u can but not sure why not. Lol is it like a Command from god? Tho shalt not gap platinum spark plugs!