Can anyone recommend to me a good non-intrusive engine diagnostic shop? My 4.6L in an F-150 truck idles rough and occasionally throws a P0302 (#2 misfire) code. I changed the plugs, coil on plug, fuel filter and cleaned the throttle bore. A local shop replaced the fuel delivery module, replaced the #2 plug again and repaired a vacuum leak. The engine still shakes at idle. The shop wants to replace the intake manifold. Rather than rip and replace more parts, I'd like a professional diagnosis. Any advice would be greatly recommended. I live in the King of Prussia area. Thank you.