This is great, and works fine as is. However, I dropped a wrench and then one of the coil seal parts (the hard plastic bit that seats in the opening for the spark plug) down the gap between the engine and firewall. It was tough to get to, and I ended up buying 2 types of pickup tool and a mirror set to get it back.

The easy fix (before this happens) is to stuff a kitchen towel size rag, or several rags along the gap and push it below the coils. Make sure it fills the whole area, then when I dropped stuff it was right there on the towel.

Where the coil doesn't have an angle to pull out, if you hook the hard plastic ring that is seated at the top of the hole and pull it out, there's plenty of room without bending anything. You pull the coil up a bit, and catch the ring with a stiff wire or dental pick. Once it's out of the way, the hole is now considerably bigger and the angle is better.

I also had a problem where the 5/8" spark plug socket stuck to the new plug after it was in, and the extension came right out. I fought that for a while to get my socket back. The fix for that is to use electrical tape to secure a 4" extension to the plug socket, then tape a universal flex joint to that 4" extension. The assembly just makes it out of the hole so you can grab it, and it works in every spot. I mated that to a 12" extension and a socket or torque wrench. The two places against the firewall were a little easier putting the socket right on the universal joint.

When I tried to remove my battery tray, the bolts were so corroded that a socket wouldn't turn them. I knew I was going to have to destroy the battery tray to get it out, so instead I just used enough force to flex the forward corner of the tray up (without the battery bolted down, and with the little washer pried out of the hole) and pull the coil out under the tray. It worked all three times and I heard the tray give some, but the part that was cracking is out from under the battery so it isn't a structural issue.

I'll order a battery tray and cut this one off next time I need in there (maybe never, but I'll have the part).

 

I've never seen someone tape a socket and extension together like that, what a great idea! I've always just kind of wiggled the extensions side to side and eventually it frees from the plug, but I'll have to try the tape...it looks easy enough and it looks like it could work.

 

My attempt to save $400 cost me $14,600 to have a used engine put in. I don't recommend replacing your own plugs. I've rebuilt about 10 car engines and a few motorcycle engines, so I'm not completely clueless. I was very careful not to get anything in there, and not to leave a plug out for any longer than necessary, yet the fact is something must have been in that deep cavity and dropped into the cylinder, destroying the engine. They say it can't be fixed.

The dealer said it could have happened to them, but they would have had to eat the repair cost.

 

I'm very sorry to hear about your engine damage however your comments above and on another thread suggest that this engine is prone for this kind of problem with a spark plug change. This is not the case at all as this can happen to any engine. I have been around forums long enough to see others that ruined their engine in the same manner. On inspection during the rebuild it was usually a washer or nut and it was acknowledged that it was the carelessness of the person doing the install.

 

Thanks for the great DIY. 70k on my LS. The air filters were just replaced and I cleaned both MAF sensors gently with Q-tips and rubbing alcohol, not dirty enough to make a difference that I could tell. The reason I'm posting my MAF finding is because the MAF is after the air filter and is unlikely to get dirty for many thousands of miles. The only exception I can think of is if you have an over oiled K&N air filter. Waiting on detailed maintenance records from dealer before doing the plugs (he said they had been done, trust but verify when buying used).

 

just did my plugs at 65k and they were i need of replacing my linear throttle response i back my hesitation is just about gone. definitely recommend replacing your plugs at 60k or before if conditions occur didn't really use the tutorial as i am pretty handy around cars. I just gotta say take precautions and use the right tool, my magnetic spark plug socket worked wonder compared to old gasket style socket, this could be had at auto zone for cheap.

 

Stop trying to deter people because you majorly screwed up. There is always a risk when doing a DIY, but you're also not telling the full story with your random spark plugs that you used and the multiple plug swaps you did.

Use the right parts, make sure that you don't crossthread the plugs, check the gap, use a torque wrench, and don't remove and leave the spark plug hole open longer than necessary and you'll be fine. If you don't feel comfortable, take Azz's advice and bring it to a dealer or mechanic.

 

i can tell you that the 460 does not like any spark plug besides the factory toyota ones. i ordered the ngk laser iridium because it was not paying attention and they didnt not do well gap was right and everything but the car didnt like it. so i put the olds ones back in the car ran okay (i knew i needed plugs) and order the oem ones, the car is smooth as butter. if you know what you are doing like stated its straight forward to change the plugs battery tray removal air filters and the bracket on the driver side and your good plus a pry bar that is needed to get the ignition coils out on a few cylinders....

 

I just did this. Exactly world for word, and it was fairly simple, thanks to the amazing DIY. Thank you.
I used different spark plugs, I don't know if I was wrong to do so. I used Autolite Iridium Xm's, which is the equivalent to the Denso iridiums. Cleaned the MAF sensors as well. Car runs smooth, we'll wait to see if the gas mileage improves.
Thanks again for the great writeup

 

Just did my plugs! I will say I didn't find it as easy to do as some others on this thread, but they're done. Thanks roadfrog for some helpful tips.

The thing I found difficult was the that the extension and socket just loved getting stuck in those spark plug tubes. I ended up using just a regular socket - after I grew tired of fighting the sparkplug socket - even then I was getting a battle. Other than that it wasn't too bad.

 

Changed my plugs today for the first time after 115,000 miles. I miss my 4 cyl !!!!! Took me about 3 hours, but I also cleaned the Mass Air Flow Sensors.

Plugs looked pretty good after 115K.

 

Look how easy it is to get to the plugs on my 1980 RX7.

 

Mine had the same small coating of oil on the threads, glad I'm not the only one. From what another member on here tells me (Devh). It's very common on Lexus/Toyota engines. Because when I first saw mine I thought..uh oh, I'll be doing valve cover gaskets.

 

Now I have to figure out what to do about the trans fluid. It bothers me not to have changed the fluid for 8 years and 115 K miles. The other 4 Toyotas I have owned I drained and refilled the trans fluid every 15-20K miles. While I'm debating the trans fluid issue, I think I will change the differential gear oil - I last changed it at about 50K miles and it looked pretty clean.

 

Does your transmission exhibit any problems.