Engine Mechanical problem
1997 Other Ford Models V8 Two Wheel Drive Automatic 95000 miles

On my last trip in my RV, the engine idle gradually increased until I no longer had to touch the accelerator to drive in highway traffic. I managed to get the motor home into my driveway, but now when I crank the engine, it immediately races up to 4200 rpm. It is a Ford 460 engine. How do I trouble shoot this problem?

Wow that is very high idle speed now what you need to do first is look for any broken vacuum lines. I would start with the one to the pcv valve and the one to the brake booster they are large and can cause a very high idle. Then I would check any of the air intake boots for cracks or brakes. If all this looks good then get back to me so we can go to the next step ok.

I figured it out myself over the weekend. I removed the main hoses leading in to the throttle body. I ran my fingers in the throttle body and felt a foreign object stuck in one of the butterfly valves. Upon removing the throttle body, I found pieces of an old air filter lodged in the butterfly valve. Here's what I think happened. When I bought the RV recently, I told them to change out the air filter, among other things. The air filter is difficult to reach, requiring you to loosen 2 screws from the inside of the cab and loosen 2 screws from the outside. I think they just loosened the 2 from the outside and literally ripped out the old air filter, leaving parts of it behind. Then, they forced in the new air filter (parts of it were bent and compressed), not realizing that they had left filter fragments inside (or not caring.) On this last trip, they were sucked up into the throttle body and gradually became wedged in the butterfly valve.

Well great glad to hear it is fixed man who would of thought of that one first off. Anyway great job and thanks