1999 Toyota Celica misfires

I have a 1999 Toyota Celica that has been a great car for about 2 years. Recently, the engine misfires causing the car to “jump”. I replaced all the spark plugs and noticed when I did that the spark plug wells were filling with oil. I went ahead and changed all the seals and the wells are staying dry but the engine is still misfiring… what is causing this?

Try replacing the spark plug wires.

Tester

Distributor cap and rotor intact and clean contacts?

I’d start off by replacing the dizzy cap, ignition rotor, and the spark plug wires. If your Celica is like my Corolla, the wires are part of the dizzy cap ass’y. So when you replace the cap, you also replace the wires. Be sure to replace the ignition rotor too though. If that doesn’t fix it, post back. Common sense says to read out the diagnostic codes of course.

Yesterday someone discovered oil in the distributor of an old Honda, keeping it from firing. Cleaned it, dried it, replaced the broken or leaking o-ring on its shaft, now it works. Worth a look.