I have a 2000 Ford e-150 van with a 4.2 engine, the check engine light comes on.

What is your question?

The engine stumbles maybe every 50 miles. I have replaced plugs, wires and a fuel pump, it has about 90,000 miles on it. I had a shop put in a remote alarm system for me about three years ago, they must have disconnected where you read the codes (it does not work). Any help would be useful.