I have a 02 chevy silverado 1500 that smoke just started coming from between the cab and the bed of the truck, then rode for about 40 miles then it free revved to 5 rpms and will not go over 40 mph
Sounds like you have a clogged exhausted converter.
Hear is a simple and easy way to check. Wait till night time and let truck run for a while then look under truck at exhaust system if converter is clogged it will turn cherry red letting you know it is clogged.
If you can, go under the truck and see if you can find any areas that may be smoldering around the catalytic converter. In the mean time don't park on grass as it will or could start a fire.
Looking for a Used Silverado 1500 in your area?
CarGurus has 148,915 nationwide Silverado 1500 listings starting at $1,800.
Search Chevrolet Silverado 1500 Questions
Chevrolet Silverado 1500 Experts