...a.m and immediate starts are ok? In the morning the truck starts perfect and if i shut it off for 5 or 10 minutes it starts fine. The problem is when the engine is warm and i shut it off for twenty minutes or more, it wont start unless i put the gas pedal to the floor and crank engine five or six times. I have tried turning key on without starting (priming) with no results. Could this be a sensor or possibly my super chip or throttle body spacer. causing this. 99 GMC sierra 5.3L
99 gmc sierra needs gas pedal floored to start when shut off for twenty mins....
- Thread starter John S
- Start date
Molson02536
New member
Fuel pressure regulator leaking fuel to vacuum lines are common in the 5.3 vortec which is what's causing rough running when started up or hard starts.
Here are some pictures of the regulator and location, as well as pictures of the fuel present on the vacuum side which should not be there at all.
http://i254.photobucket.com/albums/hh93/craigslist_album_2008/gmtruckclub/20090221_01490.jpg
http://i254.photobucket.com/albums/hh93/craigslist_album_2008/gmtruckclub/20090221_01491.jpg
http://i254.photobucket.com/albums/hh93/craigslist_album_2008/gmtruckclub/20090221_01491.jpg
http://i254.photobucket.com/albums/hh93/craigslist_album_2008/gmtruckclub/20090221_01493.jpg
Here are pics of the regulator and replacement. The new replaceent was a little different and likely an
improved design. Notice the collar which is plastic on the old one is built into the unit and metal on the
new one.
http://i254.photobucket.com/albums/hh93/craigslist_album_2008/gmtruckclub/20090221_01494.jpg
http://i254.photobucket.com/albums/hh93/craigslist_album_2008/gmtruckclub/20090221_01497.jpg
http://i254.photobucket.com/albums/hh93/craigslist_album_2008/gmtruckclub/20090221_01497.jpg
Good luck and keep us posted.
Chris_99Sierra
New member
Having the same problem right now, will try replacing the regulator. hope it works