'94 F-150 with a 351, suddenly seems to be running on 6 cylinders

Asked by Jul 29, 2015 at 06:06 PM about the 1994 Ford F-150 XLT 4WD Extended Cab LB

Question type: Maintenance & Repair

My '94 F-150 with a 351, suddenly seems to be running on 6 cylinders. Mechanic is
blaming bad fuel pumps, but truck runs exactly the same off either tank, starts right up &
idles so I disagree about fuel pumps. We hooked a gauge to the test valve on the fuel
lines & it reads 35-38 when truck was running. I'm thinking ?injectors? we replaced fuel
filter & cap & rotor. Any ideas for diagnostic or repair?

6 Answers

52,015

Are 2 spark plugs wires switched?

52,015

Switched, meaning on the wrong plugs. That would do it.

52,015

Injectors seldom go bad 2 at a time.

No, unfortunately... It happened after the truck was run on the rear tank tell empty and started to die before quickly switched to the front tank. It was driven 3-5 miles after that, parked and the next time it was started it began showing these issues...

20,130

First eliminate a possible spark problem with the plugs, wires etc. If your vehicle fuel injected. If so you could have sucked up some crud from an empty tank and fouled an injector. Also, change the fuel filter.

So I have now replaced the plug wires as well and very little if any improvement. I did run a diagnostic: ER test: Code 172-HEGO shows system always lean Code 213-Spout circuit open EO test: Code 172-HEGO shows system always lean Code 452-Insufficient input from vehicle speed sensor I can't imagine the O2 senor causing all of this... Now where to begin??

Your Answer

F-150

Looking for a Used F-150 in your area?

CarGurus has 182,094 nationwide F-150 listings starting at $1,000.

ZIP:

Ford F-150 Experts

  • #1
    OJ
    Reputation
    8,910
  • #2
    dandyoun
    Reputation
    4,540
  • #3
    tennisshoes
    Reputation
    3,060
View All

Related Models For Sale

Used GMC Sierra 1500
890 Great Deals out of 65,336 listings starting at $1,995
Used Dodge Ram 1500
393 Great Deals out of 10,914 listings starting at $1,500
Used Toyota Tacoma
604 Great Deals out of 42,670 listings starting at $1,500
Used Ford Mustang
711 Great Deals out of 38,301 listings starting at $895
Used Ford F-250
471 listings starting at $6,694
Used Chevrolet Tahoe
665 Great Deals out of 39,392 listings starting at $1,000
Used Ford Explorer
834 Great Deals out of 63,128 listings starting at $1,000

Used Cars For Sale

2018 Ford F-150 For Sale
30,907 listings starting at $20,990
2017 Ford F-150 For Sale
119 Great Deals out of 81,065 listings starting at $17,990
2016 Ford F-150 For Sale
125 Great Deals out of 7,670 listings starting at $18,989
2015 Ford F-150 For Sale
301 Great Deals out of 10,610 listings starting at $14,999
2014 Ford F-150 For Sale
434 Great Deals out of 13,784 listings starting at $10,995

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.