I have an 03 F150 with 4.2L V6. Truck was running fine to and from work. Then next morning it will crank but not start. I thought is was just a dead battery, but replaced battery and now sometimes it starts and sometimes it doesn't. I had fuel pump replace 3 months ago. I checked my fuses, replaced the PCM relay. I tried spraying eether into intake, and it doesn't make any difference. Checked and getting power to coil, but wasn't getting spark, Installed new coil, but same problem. Now it starts sometimes, and other times it just cranks but won't start. When it starts, it idles good, but when I drive and give it gas it hesitates, shakes, and is sluggish. The battery and charging system are working fine, but it is like sometimes the coil is getting and putting our voltage, and then sometimes it isn't. Today is has started every time, but still running rough. It acts like the timing is off or something, but it isn't tripping the check engine light, so Autozone can't read any error codes from the computer module. Any suggestions?

 

How old are the plugs and wires? Are you sure the new coil is good? Pull it and check it for cracks. Did you use dielectric grease in the wire boots? Are you sure you have the correct wires in the correct coil terminals?

 

The coil checked good. The plugs were 3 years old and wires even older, so I replaced both the plugs and wires, but it didn't make a difference. I noticed that the cylinder 6 plug was wet and smelled like gas, as the other plugs were dry. After I replaced the plugs and wires, the truck still runs bad and I noticed a strong fuel smell Do you have any suggestions.

 

Either #6 isn't firing, or the injector is leaking.