My 2003 fx35 coil #3 keeps burning out

Did you also replace the spark plug wires? The burn lines on the ceramic would indicate that it's jumping fire. Are the burn lines on ALL the plugs or just one or two? If you look closely at the wires in the dark, you will be able to see the spark jumping to ground if the wires are bad. If you have already replaced the wires and still have that issue, it's possible that you have a bad coil pack or ignition module.

Install new spark plugs, 4 new coils & replace the oxygen sensors

O2 Sensors are only good for 100,000 miles, then slow
down or quite

No idea why the coils do not last 5 or 6 years

Cylinder #1 is always at the front on a 4 cyl

Go to Rock Auto --Buy Wells Coils,NGK Double
Platinum Plugs & NTK O2 Sensor

Those parts are expensive because you have a Totota
Motor I guess

Clean MAF Sensor with CRC MAF Sensor Cleaner

Bad ground to motor Or coil too hot pos wire to coil try a ballast resistor to your coil 12.00 volts in creates 1200 amps 14.8 volts shorting out resistor plugs try using copper slug plugs

If you need further help, I’m available over the phone at https://www.6ya.com/expert/robert_c7b5aba9012a13b2

is there oil leaking into that plug area?

Take a compression test on # 4. It may be a little oil burning w coolant getting by the head gasket. POSSIBLE faulty injector or not firing on time. Ck for any oil in the anti freeze or anti freeze in the oil.

Hello mikew564.The first diagnosis was number 2 or 3 cylinder not firing. Once you changed the coil, the check engine light went off. When the light came back on again, did you get it diagnosed again to find out if the problem was the same?... 2 or 3 cylinder not firing????

First of all, there is NO extra wire/ground on the coil/ignition wiring (see images below). The spark plugs and ignition plug wiring can be checked for arcing, corrosion, resistance and can be checked for cracks in the insulators or worn electrodes (and spark gap) by a competent mechanic.
If you are having the same issue (2 - 3 misfire), there are several techniques for eliminating the plug wires or spark plugs. Spray water on the plug wires to see if they are arcing. Swap plugs from cylinders 2 & 3 with cylinders 1 & 4. If you still have a 2-3 misfire, check/inspect/examine the coil connector pins & coil harness to the coil(s) themselves.

I don't know how many miles you have on your car, but it is possible that you may have a spark plug being fouled out either with oil or coolant. I had a Protege with 120k and it burned more oil than gas. Change #3 plug and get a good look at the plug you remove. Look for signs of contamination.

You either have a bad ground or the bad electrical connection at the light socket is "simulating" a bad ground. This is putting a high resistance on the bulb and it's taking it's toll by burning out the bulb. I would start with a new socket, and CHECK the ground. If you still have the issue, I would run another complete ground wire and not even worry about checking the ground itself. the Stick

Check you spark plug and engine ground. if one of those is causing too much resistance then it can overload the coil.

I saw that one, on one of my cars and it was the spark plug that was loose but the car was not missing fire, it was just having too much resistance and overloading the coil.

Some how you are getting a massive voltage surge that is frying the coils. Could be a bad ground, the coils get charged up then you lose ground and the coils can’t discharge their load so they burn out. You’re probably gonna need someone really proficient with a scan tool to trace this problem down. At $500 a pop for all new coils I’d definitely give some serious consideration to taking it to the dealer or even good auto electric shop. At the very least you need to find someone with a scan tool to pull the codes and see if there are any trouble codes listed in the computer.