Spark plug Autolite or BERU

So here is my experience with gaps on this engine. The wife 09 Passat was misfiring so I decide to replace the plugs. I buy Autolite double platinums which were gapped huge. Turns out the 0.032 gap was not correct after all and it should have been 0.028. Big difference, this baby flies again (GIAC tune).

I changed the spark plugs to Autolite Double Plat plugs from Autozone. The smoke cleared up and it is MUCH easier to keep cranked in the cold (30's F) in the morning. It still has a very light stumble every few cycles and a louder engine idle than I'd like, but runs good and seems to be much better.

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.

Autolites last as long for me as the NGK's. Either of them last about 10k miles for me. Any longer than that and I start getting missfires. The Autolites can be found for about $1.00 each

the autolites are bottom of the barrel, i've only used them once when i was young and dumb and ofc they busted while trying to repair and remove after.

Yeah, get rid of those: autolite is junk.

My dad just returned a set of autolites. I installed them and had immediate misfire.

Once we got a good local supplier for Motorcraft plugs a few years ago we almost never install Autolite.

There seems to have been quality issues with those for quite a while. I couldn't count how many times we removed fairly new Autolite spark plugs and replaced them with a better brand to fix a misfire.