Abstract: The present invention provides a method and apparatus for maintaining or restoring decreasing production from a hydrocarbon or gas well using the exhaust of an internal combustion engine. The exhaust is utilized to displace or lighten the fluids in a well bore and increase the bottom hole pressure allowing the well to flow more easily with minimal or no damage to the formation that produces the hydrocarbon or gas. In another aspect, the present invention provides a means of purging and/or pressure testing production wells, pipelines, containers or vessels using exhaust gas. The present invention is a simple, effective, inexpensive and mobile means for maintaining or restoring a production well and/or purging and/or pressure testing of pipelines, containers or vessels.