PO303 code on my tahoe

[tahoeman21]

Wassup guys? I was driving my tahoe from work to home. Before i added gas, my tahoe was running just fine. So i stopped at a cheap gas station... It was Alliance gas station,,, i fueled with 87 octane.... after i putted gas... just before coming out of the gas station... my tahoe starting running like crap... it started to stumble and my check engine came on.... whenever i press the accelerator, the SES flashes and it laggs power now.

So this morning i went to a mechanic and he connected a scan tool... it showed PO303.... he said that cylinder 3 was misfiring.... he told me it could either be the spark plug or spark plug wire... so i checked for spark... there is... so the wire and the spark plug are good..... what could it be??????:skep:any suggestions????

 

[Malones99]

replace cap and rotor. don't buy a cheap cap!

 

[GMCYukalade]

Also - do another little simple test, outside at Night, Pitch black - crank the tahoe up - push the ebrake in, so the headlights go out, pop the hood, disable the Hood light, and then from there manually throttle the truck as to rev it up - look at the plug wires, down near the plugs and see if you can see the ARC, if you can than you need new plug wires - the Missfire is probably the Cap, and as suggested dont go out buying a cheap one, or you will be back in the same situation

 

[tahoeman21]

P0303 code

wassup guys? it turned out to be a fuel injector that went south.... it was fuel injector 3 to be exact.