Engine misfire?

The code says I have a misfire #3 cylinder. I have replaced the spark plugs and the coil on #3, and have tried fuel injector cleaner. The engine light (yellow) still remains on as well. The light then will blink when driving.

On my '88, misfire was caused by oil leaking down the distributor shaft into the distributor cap, insulating the lowest tower (forget which cylinder). Obviously, changing plug wires didn't help. Eventually, since the leak was non-fixable (only have to buy new diz for $400) I drilled a hole in the cap so the oil could drain. No more misfire, but oil all over the trans.

Hey Alex, changed the coil and voila she was running alright. Thanks for your help!

2001 Toyota corolla le, 183000miles, this car misfires on #4, I have switched sparkplugs, and coilpack and it didn't change the misfire, I swapped injectors and it didn't stop misfire on #4, I cleaned tb and maf sensor and didn't stop the misfire on #4, the only thing I haven't tried is compression yest. I just got car so not much info on past drive ability. It misfire whether idling or under load but mostly under a load. It throws the code for #4 misfire. Could you think of any thing else it could be

Forgot to add I checked the injector wires and the do have voltage raging from.3-.5 vdc running, and coil/plug wire has good speak also

If a vehicle that has rings going out (whatever that means) and no compression on cylinder 3 but good compression on the others could I still run it for a while as long as I keep oil in it? Seems like it might last a while, especially for short trips (50 miles or less).

More Details/History:
My 2000 Corolla has been increasingly eating oil for 18 months. In the last 6 months there were Fault codes thrown: Misfire on 3 (first), Random Misfire, Catalytic Converter fault of some kind. First time I replaced the plug for #3 no "check engine" light for a few months. Check Engine recently started flashing indicating ongoing misfires. Has some stuttering, mostly at low rpms. Recently changed plugs but made little or no difference. Mechanic checked it today and found cylinder 3 has no compression, the other cylinders have good compression. I drove the vehicle back home from far away recently (450 miles). I have free towing for 100 miles. Would prefer to drive it until it dies then tow it home to my barn (store for parts, I have another similar corolla) or junk it.

Thanks for your responses. The mechanic said bad rings would cause loss of compression eventually since the rings hold some compression for the cylinder.

As far as still driving the vehicle; What I have heard is that the catalytic converter will cause back pressure to build up and eventually blow a head gasket or something like that. But it could take a while. One person suggest I could remove the catalytic converter and go "straight pipe" as he put it. Not sure what all teh implications are of doing that.

Do you know?

Thanks Again.

I have a 2000 corolla, 129,000 miles, automatic transmision. 1.6L 4-banger. I bought the car at about 75,000 miles and in rainy weather, I heard a noise which sounded like an air leak somewhere under the hood. But, about 1,000 miles ago, I started noticing a vibration when I got up to about 40 mph. It feels kind of like a one of my tires is out of balance. So I got them rotated and balanced, which was due anyway. The vibration didn't go away. Then I noticed that the frequency of the vibration variated whithin each gear, but ONLY when I was moving. While idling, I can rev the engine and there is no vibration. I figured it was a spark problem and changed all the spark plugs, but still no luck. Last night I bought a new spark plug coil and replaced each coil one at a time. Each test showed no improvement. If it's not sparking, I'm afraid I might be burning up my cat. Could it be an injector is bad? Or compression? Or what?

Thanks

I'm sure its not an wheel problem because if I'm driving down the road and the vibrations are really bad, I can put the car neutral and the vibration goes away completely. I reengage and the vibration comes back. I've had transmission problems before and it doesn't feel like that at all. It MUST be one of three problems. 1. Compression, which is fine. 2. Ignition, which I have eliminated the problem of a bad spark plugs and coils or 3. Fuel injection, I have a fuel injector on the way and im going to perform the same test on that as I did with the plug coil. I just need some more input.