im getting a code for misfire on #3 cylinder. power is terrible especially under a load. i already changed the spark plug and the coil pack what else should i try. thanks for any help!!

 

I seem to hear alot of problems w/ cylinder #3. You should check the plug wire. If you have a multimeter, set it to 20K ohms. If the wire is good you should get between 4000 and 6000 ohms per ft.

 

thanks ill try it.

 

Also, check the heater hoses that run over the plug wires back near the firewall. I am not sure if this was corrected by your model year truck, but trucks used to have a faulty hose clamp over those wires, causing the moisture to make it's way to the plug well and foul out the plugs. The factory hose clamps needed to be replaced, and then all was well.

 

did you fix it?

 

Also check for a faulty injector