I purchased the 0-100 psi gage from ACE True value for about $8 or so and most of the fittings in the plumbing department. Fuel line from Autozone. Total investment about $15. The gage may not be the most perfect for the assignment but for troubleshooting it has been working fine for the last 4 years. Also Summit or Jegs Catalogs have a variety of gages.