F150 XLT 5.0 (302CID) SURGING & BUCKING

1994 Ford F-150

Tiny

CSA1

January, 6, 2012 AT 8:36 PM

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?

FOUND 1325 RELATED QUESTIONS

93 F150 Hesitates/surges

35 ANSWERS
5 IMAGES

Engine Surging

13 ANSWERS

13 Answers

Tiny

Docfixit

January, 6, 2012 AT 8:45 PM

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

Tiny

CSA1

January, 6, 2012 AT 8:50 PM

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

Tiny

Docfixit

January, 6, 2012 AT 9:04 PM

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

Tiny

CSA1

January, 6, 2012 AT 9:14 PM

What diagram? & What is a TFI?

Tiny

cadieman

January, 6, 2012 AT 9:17 PM

That fuel pressure is whyll the problem is happening?

Tiny

Docfixit

January, 6, 2012 AT 9:22 PM

Fuel pressure good 45 psi

Tiny

CSA1

January, 6, 2012 AT 9:29 PM

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.

Tiny

CSA1

January, 6, 2012 AT 9:30 PM

No TFI Module on this distributor

Tiny

Docfixit

January, 6, 2012 AT 9:38 PM

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

Tiny

CSA1

January, 14, 2012 AT 6:28 PM

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?

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