Spark plug Autolite or Motorcraft

I installed a set of Autolite 3923's gapped to .032 and guess what? FIXED! unbelievable, after all this testing only to find out that all I needed was new plugs.

So, I went ahead with the Autolite XP iridium plugs. Right now, I cannot complain. Everything is running pretty good. I put these in to compare to the standard Autolite copper plugs that I put in my 2001 2.0L AEG in January of 2009. Here is what has happened so far. 1. Since the new plugs, my idle rpm increased about 50-100 rpm to low 800s to mid 800s . Whether this is good or bad, I don't know. This may consume a small bit more of gas though while sitting at a stop light. 2. Since the new plugs, I can also feel a small vibration that seems to come from the engine bay. This only happens on a cold start as I am accelerating from around 15-40 mph. When it's warmed up, it's gone while accelerating. This may come my new catalytic converter and flex pipe that I just got installed, but I don't know. It may also come from new front rotors and pads that I just put in that haven't had time to properly be bedded, I don't know. I am putting some new dog bone mount inserts in within the next few days as well. 3. Since the new plugs, my engine seems to have had a small performance increase in acceleration, response, and in smoothness; except in cold start accelerations as stated above. This may not make a big deal to some, but I am happy with this. 4. Since the new plugs, the best deal I have had is the lower rpms when I am using cruise control around 40-55 mph. I am serious when I tell you that my rpms went down a good 150-250 rpms at these cruising speeds. I do believe that because of these plugs, I will get a small boost in mpg; I will let you all know shortly. Also note that only the plugs and nothing else was changed at this interval. Can I tell you what happens at 65 mph+, no because I don't go on a highway to school or work. So, my overall impression with the iridium plugs is a positive one so far. I have gone just over 500 miles since the new plugs were put in.

Good old standard Autolite Coppers work just as well as anything on the market, as long as you replace them every few thousand miles. At $.99 a piece, you can't beat 'em.

the plugs are autolite platinums AP3924. the wires are the blue ignitors from techtonics. the rest of the ignition is stock. do i regap the plugs, or should i leave them where they are now. i'm leaning towards leave them since it ran fine before and i don't want to deal with a no start issue when i start it or the first time with the new cam.

I bought some Autolite Platinums and now I find out they are crap Anyway, I needed something fast. Replaced them earlier this afternoon after work and so far so good. Acceleration is ALOT smoother.

Yesterday, I installed new spark plugs in my 2004 TJ. Going off [this thread](https://wranglertjforum.com/threads/what-are-the-best-spark-plugs-for-my-jeep-wrangler-tj-4-0.4196/) I purchased the Autolite XP985. Originally, I gapped the plugs to .04 based on [this thread](https://wranglertjforum.com/threads/spark-plug-gap-for-4-0.17415/). The jeep ran terribly and actually threw a check engine light.

I went back today and changed all the gaps to .035 based on the note under the hood, but I still think the idle is a bit rougher then what it was before the change.

I’d never put autolites in a Jeep, send em back and get champions or NGK depending on year and model.

I quit using autolite plugs somewhere between 1995 and 2000, got tired of all the comebacks.

I work on euro cars. If I'm diagnosing an issue that even has me think misfire and it has autolites, I'm done until they're in the trash can and OE is installed.

My experience with auto lite has been complete trash, and their review ratings are always great. Anybody else have problems with auto lite plugs?