Hey guys, Im usually over at another forum about my F150 but today I have a question about our 2 V10 E350 Ambulances. We have had them since brand new. I have serviced them every 3000 miles with Motorcraft 5-30 and motorcraft filter. One of them has 100000 miles on it and the other one is close to 87000. Both have a slight hiccup at idle. It is not throwing any CELS, but even with the A/C off I get feel sort of a loping. I am finally pulling doghouses and starting to do some preventative maintenance. I know the first thing Im going to do is clean to throttle body.. My question is, since these vans are run hard, would it be wise to go ahead and swap out plugs while Im under there? All the COPs are in good shape. What else should I be looking for while under there? Im used to working on 7.3s and 6.0s but this is the first V10 I have touched besides oil changes and air filters. To my understanding they do not have Fuel Filters that are serviceable because they are in the fuel tank. Any input would be appreciated. I apologize for the long post. Just looking for suggestions.