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zx2 rough idle vibration

03-01-2009, 09:40 AM
Rough idle and or vibration at idle.
OK I see this on a lot of four cylinder cars... One thing that helps is cleaning or replacing your spark plugs more often then recommended... With the motorcraft Dp plugs you can clean them and notice improvement.. I have yet to test how the iridium plugs work on these Zx2 but if anyone has any input please feel free to reply.. My nephew has a 2003 ZX2 and for the most part its been a good car.. I am going to replace his plugs.. It does have 63,000 miles on it now.. Which those Motorcraft plugs are suppose to last 100,000 miles. I Replaced mine at 90,000 on my other Ford. Overall the plugs on the zx2 had a lot of life left in them but did notice a little soot.. Which is normal.. But cleaning them help the idle out more than I thought it would.. Also runs smoother. So if anyone running Iridium plugs let me know your input on them. Thanks.

03-02-2009, 11:11 AM
I've run NGK Iridiums for about 6 months now. No problems. 2-3 more mpg. I replaced the Bosch Platinum plugs with the NGK. The center electrode is made of Iridium and the rest of the plug is pretty much standard. Iridium is 6 times harder and 8 times stronger than platinum. It has a 1200 degree hotter melting point than platinum. The .7 mmm firing electrode ( normal plugs are 2-2.5 mm) operates better for 2 reasons. (1) The smaller electrode requires less voltage to jump the gap and (2) The smaller center electrode reduces quenching. It's not the spark that ignites the mixture it's the heat of the spark. Quenching occurs when the heat of the spark is absorbed by the electrodes. Less quenching makes for a hotter spark to fire the mixture.

No, I don't work for NGK. I just did some checking on why Iridium is so good. The fuel mileage is 2-3 more mpg and my car starts and idles so much better now. Iridium are way more expensive than standard plugs, but I think they are worth it. Up until now they had no way to fuse it to the center electrode due to its hardness and and higher melting point. I know they will work good in a small engine. I am completely satisfied with them.

03-09-2009, 02:22 PM
Also if you can find them, Ford Racing plug wires help smooth the idle a LOT.

03-10-2009, 11:05 AM
Thanks for your reply.. Yes I use those NGK in Honda's and a few Toyota's..

Seeing how some Fords act funny when you put a more expensive plug in it I wanted to make sure.. I can not run any other plug other than Motorcraft or Autolight DP in my Ford Van or it runs like crap.. Don't know why but others have same problem as well.. Just wanted to see if the 4 cyl worked better with the iridium plugs. Thanks..

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