I'm no expert, but the fuel pressure could be low, making the computer decide to go to full open on the fuel injectors in order to get enough fuel into the engine. The dealer may not have wanted to check the fuel pressure because it is sometimes hard to find a place to tap into the fuel supply line. On my son's Chevy pickup I had to get under the truck and replace the fuel filter with a "T" connected to a gauge. There was no where else to check the pressure. If the fuel pressure is low, it could be a bad fuel pressure regulator or a bad fuel pump or a plugged fuel filter. There's a related problem referenced about halfway down the page on this reference: http://www.2carpros.com/topics/rough5.htm Good Luck, Joe Fulton Salinas, CA --- oconner_us@xxxxxxxxx wrote: > My boss has a 1990 Ford F-150 with 6 cylinder and > auto tranny. > Jamie Smith > oconner51@xxxxxxxxxxx > > ============================================================= > Posted by wixList Archiver -- > http://www.amxfiles.com/wixlist > > > > > >