1994 FORD F150 XLT 5.0 (302CID) SURGING & BUCKING

  • Tiny
  • CSA1
  • 1994 Ford F-150
  • 210,000 miles

Truck cranks and runs, When Idling, engine surges. Gets worse when you drive it down the road. Will surge & buck after 40mph. Replaced throttle position switch, coolant sensor, distributor, cap, rotor, plugs & wires. Removed upper intake, cleaned it out. New gaskets, cleaned throttle body including EGR ports, replaced MAP sensor, and replaced fuel filter. Seemed to help for about 15 minutes, then began surging & bucking again. Any suggestions as what to try next?

Friday, January 6th, 2012 AT 8:36 PM

13 Answers

  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Have you checked for codes? Fuel pressure correct? Same colde as warmed?

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 8:45 PM
  • Tiny
  • CSA1
  • Member

Fuel pressure was 49 psi. Only code that shows is MAP sensor, which I replaced, but code still comes up. & Yes, runs same cold or warm

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 8:50 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

See diagram Dist look like it? If yes remove TFI have tested VERY prone to cause problems.

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 9:04 PM
  • Tiny
  • CSA1
  • Member

What diagram? & What is a TFI?

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 9:14 PM
  • Tiny
  • cadieman
  • Expert
  • 3,785 posts

That fuel pressure is whyll the problem is happening?

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 9:17 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Fuel pressure good 45 psi

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 9:22 PM
  • Tiny
  • CSA1
  • Member

As far as I can tell, fuel pressure to engine is ok, it seems to get plenty of fuel. Shows 39 PSI at the post on the fuel rail. (Miss typed the last one, not 49) As long as you give it gas, it runs great. Has a little miss, but once you let it idle or hold at a steady speed, it surges, & bucks like a mule.

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 9:29 PM
  • Tiny
  • CSA1
  • Member

No TFI Module on this distributor

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 9:30 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Truck is late 94 so Dist has shutter vane and ICM see diagrams locate and have ICM tested

Was this
answer
helpful?
Yes
No
Friday, January 6th, 2012 AT 9:38 PM
  • Tiny
  • CSA1
  • Member

Had Ignition module tested, passed ( cycled 25 times )
Would the IAC cause this problem? I know it might at idle, but would it cause the problem while driving as well?

Was this
answer
helpful?
Yes
No
Saturday, January 14th, 2012 AT 6:28 PM

Please login or register to post a reply.

Similar Questions