OK, new plugs and wires are in. Took me 2.5 hours (yes, I'm slow). Old plugs really didn't want to come out! They all looked pretty decent (not wet, etc.), but definitely well used. On the drivers side, the gaps were off the gauge (well over 0.080). The ones on the passenger side weren't much better (about 0.070).
Truck doesn't show any improvement. Still idles low (600 rpm when warm), and has a definite vibration you can see (engine shakes slightly) and feel (vibration through seat, wheel, etc.).
Took it to the local garage, says he has the same truck, with the same mileage, and same symptoms (although his doesn't vibrate quite as much). Said he knows it won't throw a code, and doesn't see a reason to just throw money at it (such as the Ford mechanic was guessing it's the harmonic balancer). He said just drive it...
The Ford mechanic said if you can feel the weight moving inside the pulley, the part is bad. My local mechanic said he never heard of these trucks needing to have that part replaced.
What do you guys think? Is it worth replacing the harmonic balancer just in case? I don't want to waste money, but I really can't afford a catastrophic breakdown.
Mike
