Plug & Wire Change Screw Up????

[BB]

Where did I go wrong!

Just changed the plugs and wires on my '03 GT at 60K miles. New NGK Iridium IX plugs and Magnecor wires.

Ran fine before the change. Now bogs down on take off...misses at 3K when reved in the driveway.

1st screw up?: Gapped the plugs to .40 Gap too small?

2nd screw up?: Just noticed that the wires I was sent say they are NOT for use on the GT. Could that have this kind of affect?
Curious,
Bill

[quicksilverdon]

Hope you meant 0.040 not 0.40 gap. 0.040 should be okay, many feel an even smaller gap is better.
Wires should be the same whether turbo or not.
What I suspect is you may not have a wire or 2 seated - push on them real hard and feel the "click" - I found the fresh wires were tough to get clipped on right.

[CREWZIN]

Hopefully, your used the Anti-Seize on the plugs threads and Dielectric Grease on the plug wires.

Agree with QSD on the wires. There are some Magnacore ads that say "Not for Turbo" and others say 01-05 all models, but most other brands make no distinction between Turbo and Non-Turbo.

Make sure you didn't take off or loosen any vacuum lines while gaining access to the wires.

[hharper1321]

quote:Originally posted by BB

Where did I go wrong!

Just changed the plugs and wires on my '03 GT at 60K miles. New NGK Iridium IX plugs and Magnecor wires.

Ran fine before the change. Now bogs down on take off...misses at 3K when reved in the driveway.

1st screw up?: Gapped the plugs to .40 Gap too small?

2nd screw up?: Just noticed that the wires I was sent say they are NOT for use on the GT. Could that have this kind of affect?
Curious,
Bill

First of all. Calm down. Take out those iridiums and gap them to 0.028, then put them back in with antiseize, and seat the wires with dielectric grease. And the reason you break up at 3-3.5k rpms when revving on your driveway, is that the PT has a Park and Neutral rev limiter. It cuts fuel just past 3k.... Oh, and you could have saved some money and just went with NGK 4306's gapped at .040. I wouldn't bother with iridium unless you are getting into some real high hp situations, and you aren't....

[BB]

Thanks for the tips folks!

Couldn't get back under the hood today but I will tomorrow.

Yeah...I meant .040, not .40 Stock plugs installed by the dealer were at .075...is that normal?

Yes on the anti-seize. Yes on making sure the new wires were seated well on both ends. Never had a miss at 3K when reved before...that one is curious. As for the wires, the only difference I can think of to make one set turbo rated and another not would be the heat under the hood??? No issues with vac lines that I know of but I'll check carefully tomorrow.

I'll regap to .028-.030 first and see if that helps. If not, I'll put the old wires back on and see what happens. If none of that works, I'll throw the old plugs back in and see if it normalizes before going any further. I'll post results when I have something.

Thanks again for the info!
Bill

[Mean Green]

"plugs installed by the dealer were at .075...is that normal?"

No [xx(][xx(][xx(][xx(][xx(][xx(]

[quicksilverdon]

quote:Originally posted by Mean Green

"plugs installed by the dealer were at .075...is that normal?"

No [xx(][xx(][xx(][xx(][xx(][xx(]

Agree. In the manual, gap is 0.050, later revised by TSB to 0.040 (stated for non-turbo, but works for turbo, too).
How long ago did dealer put plugs in? I read that gap usually widens over time, but 0.075 is a lot.....

[BB]

Wellll.....got back under the hood tonight. Tried the old wires first...still at .040 on the gap. Still stumbled from idle and wasn't smooth.

Regapped to .030-31...a little better...not as much stumble and smoother revs overall.

Regapped to .028...hard to be really exact with the crummy gap gauge I have...better all the way. There still seems to be a little "roughness" between 1K - 2K but it's very drivable at this point. Before, I was afraid to drive it down the block due to the stumbling/lugging at take off.

Soooo...I'm back in the driving game at this point. My only question is should I regap to something like .026 to see if it will smooth out any more...or should I stay pat and see how she does over the next few days??
Thanks for the feedback all!
Bill

[littleblueGT]

BB,I think that there is another problem! I have an 03 GT with NGK Iridiums gapped at .045 and it runs great.Provided your coil is in good shape and the plug wires are good changing the gap shouldn't be required.If you can check the resistance of each wire you would know for sure that there is not a problem with the wires. Were you careful with the antiseize so as not to get any on the plug tip or insulator? There was also a tsb to replace the PCM in the 03 and mine ran smoother after that change. Did you disconnect the MAP sensor before changing the plugs? I usually do due to the close proximity of plug #2 and the ratchet wrench.Check the harness going to the coil where it rubs on the front valve cover, and insure its plugged into the coil and locked.It's probably something simple, but not the plug gap.

[BB]

Hi littleblueGT!

I have an 03 GT with NGK Iridiums gapped at .045 and it runs great.
Yeah, I figured .040 would be a good starting point but it didn't run worth spit!

Provided your coil is in good shape and the plug wires are good changing the gap shouldn't be required.If you can check the resistance of each wire you would know for sure that there is not a problem with the wires.
Coil is still the original as far as I know. I could measure the resistance of the new wires and see what they show.

Were you careful with the antiseize so as not to get any on the plug tip or insulator?
Yep, I kept it on the threads only.

There was also a tsb to replace the PCM in the 03 and mine ran smoother after that change.
Hmmm...didn't know that...maybe I should look that one up.

Did you disconnect the MAP sensor before changing the plugs? I usually do due to the close proximity of plug #2 and the ratchet wrench.
Yep...made sure to put it back on...that's the kind of thing I am bad about.

Check the harness going to the coil where it rubs on the front valve cover, and insure its plugged into the coil and locked.
Will do but everything looked okay tonight.

It's probably something simple, but not the plug gap.
That wouldn't surprise me but it's hard to argue with the results I got tonight...every decrease in gap made it run better. I'll see how it does over the next couple of days.
Thanks!
Bill