Problem with '02 Mitsubishi Mirage Stumble and stutter

The problem started back in December 05. The temp got so low that there was a danger of gas lines freezing and I didn't have much fuel in my tank. I went to the gas station that night and filled up my tank but I noticed some hesitation. The next morning I noticed more hesitation and got some water remover for the fuel lines. This seemed to help for a moment but the problem returned. Since then I've replaced the fuel filter, coil packs, spark plugs two times, both 02 sensors, the MAP sensor, and checked and cleaned the injectors. I backprobed the Throttle Position Sensor and it gave me the correct reading. Any suggestions? Please help.

any codes? which ones? what kinda mileage, what engine, what's the fuel pressure,

The code is P0302 (misfire on cyl 2) and the mileage is 130,000. Haven't checked the fuel pressure.

how did you check/ clean the ful injectors? did you switch cyl#2 with another one, Is the resistance value the same for all of them, Have you done a compression test?

I removed the fuel rail and wiped the tips clean with some gas then switched #3 with #2 injector. Replaced everything and the engine idled smoother but when I test drove it, the code came back on cyl 2 again. Haven't checked compression yet. While I was under the car replacing the rear O2 sensor, I noticed the shield on the catalytic converter was a bit damaged too.

do a compression test, doubt the cat has anything to do with this

I'll give it a test tomorrow afternoon. (1.8L engine)

Thanks
Andre

so how old are the spark plugs?

Plugs are only a few months old. I checked the compression and it looks good at 180psi

Is it true that since I disconnected the fuel rail I have to have the computer recalibrated before it will display new codes? I have a Code reader that gives me P0302 code and someone told me I needed to have the computer recalibrated before I can get the real problem code since I removed the fuel rail.

doubt it unless there was some kind of sensor on the fuel rail, recheck for a vaccum leak around the o-rings for the fuel injecors and the rest of the intake and check the connector at the misfiring injector with a noid light to be sure the pcm is pulsing it. When it's running is there a misfire you can feel?

The noid light shows the injector is pulsing. While running there is a stumble that feels like its misfiring. That plug (#2) is always more burned that the others upon removal. A slight bit of oil or dark fuel around the threads but not on the tip of the plug.

Is there a vaccum leak?, Sounds like an engine issue to me, sometimes compression tests don't reveal everything. do you know how to do a cylinder leakage test? so it isn't a coil on plug system? Nobody's done a timing belt or some other similar job to this car recntly have they?
I'm just wondering if the belt is slipped. Does it have an EGR valve because i have seen egr valves cause misfire dtcs? Maybe you have alot of carbon on the valves?

good luck and keep me postted

jeff

This problem was resolved. It happened a couple more times. Stumble and stutter with code indicating misfire on cylinder 2 tends to be a bad coil rubber boot. about $70 for the kit from Advance Auto. Pop the bad one off, put the new one on and "bamm" problem solved. It is triggered by running the car with a bad alternator. If the power goes to and the car shuts off, a surge of electricity burns out the coil boot.

So the new coil had a bad boot?