I have a 2001 caravan with the optional, check engine light always on, option. I was running down the hi-way at 100 kph (60 mph) today with a full tank of gas, the low fuel warning bong, sounded and the gas gauge bounced from full to empty back to full for about 5 min. the van kept running great, with no difference in power or sound. What could the problem be? after about 5 min. everything returned to normal and it ran just fine for the rest of our trip. The details are, wan was warm and had been running for an hour'ish. van is in good shape but has a check engine light that has been on the entire time I have owned the van. (more than 2 years) full tank of gas. any help you could offer would be great
thank you in advance.

 

If you could post the code(s), that would help a lot. Turn the key from off to on quickly 3 times and the codes will display. Ignore P1694.

 

Common failure for your gauge problem is the fuel level sender in the fuel tank. It's part of the fuel pump assembly. It won't effect the engine. It's just for fuel indication.