'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

49,295

Are 2 spark plugs wires switched?

49,295

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

49,295

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...

19,340

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

Add photo

Related Questions

F-150

Looking for a Used F-150 in your area?

CarGurus has 193,347 nationwide F-150 listings starting at $290.

ZIP:

Search Ford F-150 Questions

Ford F-150 Experts

#1 OJ
OJ
Reputation 8,490
#2 dandyoun
dandyoun
Reputation 4,420
#3 tennisshoes
tennisshoes
Reputation 2,950
View All

Related Models For Sale

Used GMC Sierra 1500
774 Great Deals out of 68,507 listings starting at $1,800
Used Dodge Ram 1500
403 Great Deals out of 10,927 listings starting at $1,000
Used Toyota Tacoma
529 Great Deals out of 42,960 listings starting at $1,995
Used Ford F-250
465 listings starting at $4,390
Used Ford Mustang
680 Great Deals out of 44,707 listings starting at $1,500
Used Chevrolet Tahoe
585 Great Deals out of 32,920 listings starting at $1,500
Used Ford Explorer
889 Great Deals out of 64,222 listings starting at $799
Used Ford Ranger
169 Great Deals out of 5,600 listings starting at $900

Used Cars For Sale

2018 Ford F-150 For Sale
873 listings starting at $29,070
2017 Ford F-150 For Sale
75 Great Deals out of 123,863 listings starting at $18,199
2016 Ford F-150 For Sale
116 Great Deals out of 9,443 listings starting at $14,950
2015 Ford F-150 For Sale
219 Great Deals out of 8,925 listings starting at $15,990
2014 Ford F-150 For Sale
334 Great Deals out of 12,545 listings starting at $9,900

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.