89 F-250 5.8 4x4 Runs rough

Asked by Mar 17, 2017 at 07:47 PM about the 1989 Ford F-250 STD Extended Cab 4WD LB HD

Question type: Maintenance & Repair

As i was driving it the truck kept losing power. Finally got to a point it
wouldn't run to move it. The hose from EGR down to exhaust blew apart. I
have replaced that.... converter isn't plugged. We have replaced oxygen
sensor, MAP sensor, EGR.  We have new fuel pump, the correct fuel
pressure. Truck will start and stay running now but rough. Plugs if pulled
will be wet like it is flooding out but when we add carb cleaner it smoothes
out and runs fine. Any suggestions on why it would run so rough? Like the
fuel to oxygen level is out of balance..... what else could we check?

4 Answers


Check for vacuum leaks. Use some carburetor spray cleaner, and spray along the intake manifold gasket, and the throttle body base gasket, you would notice a change with the rpms of the engine.

Gaskets have been replaced....all vacuum lines seem to be ok.


If all else fails, check the compression. Maybe you have a worn engine or a bad cylinder.


Could be the fuel regulator. It still would start up. You can test that in place with the engine running by hooking up a fuel pressure gauge, then pull the vacuum line off of the fuel regulator. The fuel pressure should rise about 5 to 8 lbs. Also rev the engine up and see if it holds the proper fuel pressure.

Your Answer:


Looking for a Used F-250 in your area?

CarGurus has 411 nationwide F-250 listings starting at $3,500.


Ford F-250 Experts

  • #1
  • #2
  • #3
View All

Related Models For Sale

Used Ford F-150
2,230 Great Deals out of 209,289 listings starting at $1,300
Used Ford F-350
216 listings starting at $4,999
Used GMC Sierra 1500
698 Great Deals out of 60,847 listings starting at $1,395
Used Ford Mustang
273 Great Deals out of 37,583 listings starting at $1,350
Used GMC Sierra 2500
127 listings starting at $4,800

Used Cars For Sale

1996 Ford F-250 For Sale
55 listings starting at $3,500

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.