I just replaced the spark plugs, since Lexus said mine had 90,000 miles on them and needed it. I ordered a set from Rock Auto, and after installation, my car was pinging and rattling like it had gravel in each cylinder. I pulled them out and discovered they're about 1/4" shorter than stock, which could have been it.

I went to the store and put in all new platinums that look like they fit. The car still did that scary sound for 20 seconds then smoothed out and put up a check engine light.

Did I do something wrong

 

You have to use the stock plug, I believe they are Denso's, but I'm not sure. Somebody else would be able to tell you what exactly they are.

Going to the parts store and putting whatever their computer tells them "fits" your car, is not going to cut it. Believe me that is a common problem with a lot of higher end cars, it leads to pre-ignition (ping), check engine lights (misfires, rich conditions, lean conditions, cat damage).

Just be glad the first set of spark plugs you put in were too short, and not too long...then you'd really have problems. The bad news is you are going to have to take those plugs out and put the right ones in - you can buy a set on ebay for around $110.

 

Edited.

Get the right plugs. You'll be fine.

 

I agree with the posters above. Also using a platinum application where iridium plug is used can have misfires because the spark kernel will not be as strong.

What might have happened is that you had a series of misfire conditions that tripped a check engine light. You will need a scan tool to clear it or disconnect the battery for five minutes to clear the code and everything should be fine.
Always use factory plugs.

 

Uh no....I doubt that. Regardless, I posted a DIY on spark plug replacement and is in the Stickies section. I'll save you some time:

https://www.clublexus.com/forums/ls4...eplacment.html

As for the plugs, I used a set of Denso Iridium Long Life which are OEM and got them on Ebay with free shipping. Part # is FK20HBR11 also known as part# 3473. Don't use anything else. Thhis as the best prices on Ebay right now (70-85 bucks for a set of 8):

http://www.ebay.com/itm/TOYOTA-LEXUS-GENUINE-SET-OF-8-FK20HBR11-Iridium-Spark-Plugs-/261897038158?hash=item3cfa47a94e&vxp=mtr
http://www.ebay.com/itm/DENSO-FK20HBR11-3473-LONG-LIFE-IRIDIUM-PLUGS-8PCS-/221773848379?hash=item33a2c05f3b&vxp=mtr

 

I always use oem spark plug replacements. When I had my 96 impala ss I went with what I thought would be a spark plug upgrade and had this same issue from Summit Racing.

If you aren't building a performance setup oem is the way to go imo. Sometimes a visual inspection of each plug and regapping is all you need vs. Replacement.

 

If you've already got 96k miles (as the OP does), and you've gone through all the effort of removing them, you may as well replace them.

 

Yes ... but some items like spark plugs don't have to be replaced on a time schedule it's simply recommended. When you take them out if you know what you are looking at as far as different wear indications you can tell a lot from a simple visual inspection. Just saying... I just replaced my original oem waterpump at 160k... i visually inspected it every 2 weeks for the last 3 months and only changed it because i knew I was pressing my luck.

Not saying op should go 160k on original plugs... just saying they don't have to always be replaced at 90k 180k

 

Sorry, after checking the box again, the plugs that are in there now are iridium Autolite iridium XP, which look the same length but only have one tab around the electrode, not 3. I also noticed the plug gaps were about .045 and some maybe wider. I see the part number you mention has a gap of 0.40.

I stupidly didn't check first and didn't think that would matter much, but after I put a few in I noticed a gap tool in my toolbox and checked the rest. Obviously something matters a lot, so is the car really seeing the gap difference, or the lack of the other two electrodes, or what?

Are you saying I need to put the stock plugs back in until I can get the right ones ordered, or are you saying if I clear the codes these iridium plugs will work?

I can't leave my only car out of commission while I wait for the mail (no doubt I will buy factory plugs, but I may just take it to the dealer and have it done right).

I'm not crazy about putting the stock ones back in and pulling them again in a few days when the right ones show up. I'm going to wear out my connectors having a total of 4 spark plug changes to get it right once (yes, my fault and I deserve it, but the wires don't).

 

What you do is up to you and varies based on your circumstances. Is the car running smooth? Have you driven it? Have you called Rock Auto to determine what they did wrong and whether they'll make good on the proper plugs? Are you near a dealer or source for the Denso plugs? If your car is running as it should, then I would wait until you get the Denso's. If it isn't, then you have more pressing matters and need to get the Denso plugs ASAP. Try your Toyota dealer or local parts store, like NAPA, Pep Boys etc

 

Thanks! I checked out your replacement post (wish I would have done that first) and l like it. Nice work. Does carb cleaner work on the MAF? I'm guessing not, or they wouldn't have a different can.

 

Use only maf or electronic cleaner on the maf sensor.

 

I would put back the stock plugs and wait for the new plugs. I have heard bad things with Autolite plugs on Toyota applications. I only trust the stock Denso and NGK that are designed for Toyota engines.
When you get new Denso or NGK plugs they will allready be properly gaped but it doesn't hurt to check them.
I wouldn't worry about the connectors or coil packs because they are durable for many spark plug changes. The only thing that would worry me if I didn't replace the spark plugs with full awareness that I should not cross thread them and if I didn't use a torque wrench.

 

MAF cleaner only. Again, it's available at your local auto parts store. Electrical contact cleaner is said to work as well, but the propellant in it is different than in the MAF cleaner.

 

Make sure to visually inspect and compare the gaps on the plugs. Iridium plugs should be pre-gapped and you shouldn't gap them, however I have run into several instances where the iridium spark plug's gap was too small and I had to exchange it for a new one. This simple inspection saved me the trouble of having an engine that runs poorly and having to pull the plugs again.