My car has an unusual problem. It gets the same fuel economy at 90MPH as it does at 60MPH and it doesn't like to start when cold. The malfunction indicator light is not on and there are no stored dtcs. Once the car is warm, it runs fine except for bad highway fuel economy. (21-23MPG instead of the usual 25-28MPG) . I think we found the problem. The fuel pressure is out of the specified range. Chrysler says the fuel pressure on the LH platform cars should be 58PSI +/- 5PSI..... this car ranged from 36 to over 75 PSI. It's time for a new regulator. These cars have returnless fuel injection so the regulator is not on the fuel rail, rather its on the fuel pump itself. As the rpms increase, the pressure stabilizes which explains the bad fuel economy at lower speeds and OK economy at high speed. The gauge is an Actron/Sunpro unit picked up at Sears for $40. Check out this car and a whole lot of other sweet LH cars on lhforums.net!

Related posts:

  1. Actron CP7817 Throttle Body Injection Fuel Pressure Tester
  2. PLX Kiwi OBDII Scanner and Fuel Saving Device
  3. How To Diagnose Problems With Your Car
  4. Amazon com PLX Kiwi OBDII Scanner and Fuel Saving Device Automotive