BurbMan wrote:
jspringator, you mention the shudder is at 1500 rpm and below, so assume it smooths out at higher RPM? If so that wouldn't indicate an ignition problem....as supported by lack of codes...if one or more plugs wasn't firing the miss would be more noticeable at higher RPM.
My experience matches his. The V10 is a smooth running engine, and a miss is most noticeable at low RPMs. When my coil failed it really was only noticeable in OD below 50 MPH. But mine did set a code. A weak coil won't set codes until it completely fails. Had that problem on a 2000 Jaguar S-type (same 3.0 V6 used in other Fords). One or more were weak. Codes said "Multiple Random Misfires" so I changed the plugs. That cleared the codes, but it still had a slight miss at lower RPMs, mainly under load such as climbing a freeway grade (6.5% in Portland). Ended up just changing all of them because half the motor is buried under the intake.
