I just want to write this to put down for posterity for others to be able to find what I couldn't find on my own but with my friends' help, I was able to solve the problem.
The 1998 Toyota 4 cylinder has over 100,000 miles on the original four NGK BKR5EYA plugs & four wires & two coils & (how many?) fuel injectors.
Last week, the yellow emission-control OBDII Check Engine Light lit solid (not blinking so it wasn't that serious) and a friend checked it this weekend to tell me the code is P0301 misfire detected, P0303 cylinder 2 of 4. I had noticed the engine running a bit roughly under acceleration for about a month but I wasn't sure what the cause was.
I called Toyota this morning and they said plugs and wires would not fix this cylinder-misfire diagnostic code and the Toyota 4Runner needed to be brought to them for service because it could be the ignition system, the 200-dollar fuel injectors, the 100-dollar ignition coils, the fuel system, the EGR system, the engine congtrol module computer, etc. They were clear that just replacing the plugs and wires would not solve the problem. I needed an 800-dollar diagnostic service.
Undeterred, my kind friend bought four new two-dollar ND K16R-U spark plugs, gapped them to 0.031 inches and torqued them to 14 foot pounds in the Toyota 3RZFE 2.7 liter 4-cylinder engine. Unfortunately he also had to replace the 50-dollar four spark plug wires on the two coils because two of the wires broke at the spark plug, necessitating needle-nose pliars to pull the stuck-on metal caps off the plugs.
For 30 seconds, we removed the 15 amp EFI fuse in the engine compartment next to the battery, which reset the OBD II memory.
Time will tell but the yellow emissions control check engine light stayed off during a test drive and the prior stumbling disappeared. I'm amazed that plugs would last 100,000 miles (they were the normal j-gap type, not even platinum).
This is written so that you may comment to help us and others. The main problems we ran into were the Belden ignition wires didn't stay on the coils as the clip was about a tenth of a millimeter too small so it took about fifteen minutes to get the coil side of the wires on correctly.
The only other problem was that two of the ignition wires broke at the top of the plug, necessitating needle-nose pliars to extricate them. As recommended, we used no lube on the spark plug threads so we can rest assured the 14 foot pounds is accurate.
Does anyone have a recommendation for a good inexpensive OBDII scan tool for future events?
(I had a borrowed OBD II scan tool and we reset the yellow CEL by pulling the EFI fuse but it would have been nicer to have an inexpensive OBD2 scan tool.)
Where is the best place to get a good cheap OBD 2 scan tool? Is there any freeware for the Windows XP PC? Where would we get the cable from the OBD II port to the computer ports?
How abt one you can leave hooked up all the time and monitor everything in real time such as gas mileage?
Well, You got some bad service recommendations from the dealer, that is no surprise.
But, unfortunately, the torque spec of your spark plugs could have been largely ignored as you do *NEED* to put an anti-seize compound on the threads of any aluminum head engine when replacing the spark plugs.
What you may end up with is a spark plug that will not come back out when it's time for replacement or it even may "blow back" out of the hole!