My '01 ranger suddenly started running rough. I figured It was misfiring so I took it to the auto parts store. They did a diagnostic and it said that #1 was misfiring. I bought plugs and will replace all of them tonight. Does that seem like the problem? I am hoping someone has had similar circumstances

I changed out the spark plugs and it did not fix it. I changed the wire for the #1 cylinder and still no change. Any suggestions??

are you getting spark at the plug? check the injector signal with a noid light.

Thanks I will check the spark. I have never heard of a noid light. can you get them at most auto parts stores?

The plug is getting spark. Does that make it an injector problem?

Yea it might be the injector, open wire, or even the ECM. The noid light is just a test light for checking the injector signal.

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I will try that out. If the light is off would that be the wiring most likely? The vehicle has 65k so it is probably not the injectors I hope. Thanks for your help cctxfish!!!!!

probably ECM, my guess, you can tie it into another injector signal

It was the ecm!!!! They called it the ignition coil but I think it is the same thing. None of the auto parts stores in town had the part so I had to pay the dealer $120 for the part. ouch!! But it was fixed a lot cheaper than having it serviced. Thanks for your help cctxfish.