95 460
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
It's not that it will increase as it warms up, but think of an old carbed engine you used a choke to richen it up, well higher fuel preasure will do the same thing so it will run fine cold but then as it warms up it will be running too rich and cause it to run rough except at full throttle.
recommended fuel preasure is 35-45.
Forgot to ask do you have a check engine light or any codes? there are other things but with your description fuel preasure would be the first place I would look expecially since it's easy enough to check, you know check the easy stuff first.
recommended fuel preasure is 35-45.
Forgot to ask do you have a check engine light or any codes? there are other things but with your description fuel preasure would be the first place I would look expecially since it's easy enough to check, you know check the easy stuff first.
Post Fiend
Joined: Nov 2000
Posts: 6,060
Likes: 7
From: Glendale Arizona
Tap on the IAC idle air control motor. It is the tublar unit in front on top of the lower intake under the throttle body. It allows fresh air into the intake during cold start increasing idle speed.
Leading cause of rough running after warmup. it allows additional air in during cold start. Its the choke of the EFI era. if it is hanging up it will fool the MAP sensor into thinking the vaccume has dropped and will dump additional fuel in to bring the vaccume within tolerance as it will not believe the TPS signal as the temp sensor will show warm temps.
clear as mud but a cleaning or replacment of this little buggher has worked on every EFI ford i have owned.
Garbz
Leading cause of rough running after warmup. it allows additional air in during cold start. Its the choke of the EFI era. if it is hanging up it will fool the MAP sensor into thinking the vaccume has dropped and will dump additional fuel in to bring the vaccume within tolerance as it will not believe the TPS signal as the temp sensor will show warm temps.
clear as mud but a cleaning or replacment of this little buggher has worked on every EFI ford i have owned.
Garbz
