Cylinder 3 misfire

[kentk1]

Hi all, my daughters 97 Corolla DX is throwing a P0303, cylinder 3 misfire code. After reading through the forums, I have done the following:
Replaced plugs with NGK's
Replaced original spark plug wires
Replaced dist cap and rotor
After doing this, it ran fine for about 3 weeks, now throwing the code once again. My next thought is to switch cylinder 3 injector/coil with another cylinder and monitor.
Any thoughts or input would be much appreciated. Tired of driving between Tucson and Phx to work on cars..thanks
Kent

[Rip The E Brake]

I would try a junkyard coil and or distributor.

[CRASHDRIVE]

problem with portable code reader is it tells you the problem but it wont tell you the causes, I have is a Engine Diagnostics Software its like a OBD-II code reader but it tells you more and what to check, it also tells you location of the part by make and model of the car.

P0303 code tell you the cylinders #3 is not firing properly, lets eliminate the spark plug, wires and dizzy rotor & cap since you changed it, if you have an volt/ohm meter check all fuel injectors. EDS also tells me to check for the following.

Faulty coil (pack)
Faulty oxygen sensor
Burned exhaust valve
Faulty catalytic converter
Poor compression
Defective ECU

I took out the spark plugs and everything you changed and may checked but the EDS goes to the highest probability to lowest so the lowest is a defective ecu.

[kentk1]

thanks so much...the document I have shows resistence at 13.8 for the fuel injectors, do you concur?

[CRASHDRIVE]

Originally Posted by kentk1

thanks so much...the document I have shows resistence at 13.8 for the fuel injectors, do you concur?

right on the money 13.8ohm resistance but my FSM says low 13ohm to high 16ohm I think the high are for after market

[kentk1]

thank you all so much....I ran into a time crunch so had her take to the shop. Replaced the #3 injector and cleaned the other 3. Running like a champ now...so I guess it saved me from spending $$ on a coil I did not need as I was going to replace that next and then move onto the injectors.....

[speedy25]

Hmmmmm... interesting that the list of potential solutions didnt include a bad injector. I had a misfire code happen in my Dodge van, but I knew why.... I ran out of gas!

I'll postulate that any misfire code is probably NOT ignition related.

Glad you found the trouble semi easily and without throwing lots of money at your car.

-SP

[fast68]

bad injectoro, coil, or plug

see if the plug is firing

if not then replace what is causing no spark

if it has good spark then try another injector

most of the time its a bad injector

but sometimes its not


weve been replacing bad injectors often here

mostly on domestic cars though

seems to be really rare on foreign cars


if you need a good one i may have one from 93 1.6L

because new ones are $$$$$$$$$

[kentk1]

Sorry for the massive delay, was out here looking for something else and came across this...it was a bad injector...replaced with new one and sent the others out for cleaning...ran great for a few months, now getting a little bit of sluggish acceleration, but not as bad as before..geesh....maybe should have replaced all of the injectors?? Oxygen sensor?? is what I am thinking now....
thanks
Kent