My 79 f150 started backfiring & now wont start

Asked by Sep 15, 2015 at 06:38 PM about the Ford F-150

Question type: Maintenance & Repair

I was driving My 79 F150 351M, down the freeway it was running good, had to stop quickly due to traffic, so I down shifted and braked, the truck started running sluggish and backfiring when I tried to accelerate then died, now it wont start and backfires when I do.

6 Answers


How many miles on her? And that's the 351 M 400?


It is possible that the timing chain has jumped time or broken. You will need to do a compression test to determine if this is the problem. How many miles on it. Have there been any recent repairs.


What ever you find you need to access if it is even worth fixing. I had a couple of 351 M 400s and took good care of them. Sorry to say they only go 115,000 miles before needing major repair. They are junk. At the time, any one I knew who had one they had problems at the higher mileage. Now a days 100,000 miles is nothing. But were talking the 351 M 400, Not the 351 Cleveland motor.

It is a 351M that was rebuilt at 300k, now only has maybe 20k on it, the OD isn't working. When it was rebuilt I had a double roller timing chain and gears installed, I am hoping its not that.


Well then lets get-err going, listen to Bobs input, very knowledgeable, I hope you have it somewhere so you can work on it. I myself seen this once before, and it had to do with timing. Do you know how to work on it? or have a hand. I would look at timing first, #1 TDC on compression stroke, see if rotor is pointing at #1 plug wire. It should be there. If not I have seen where the pin on the distributor gear shears, so would need to pull distributor out and inspect the gear. Let us know from there, and we'll continue to help.

1 of 1 people found this helpful.

Well, with a double roller timing chain and gears 20,000 miles ago, that leads me to think something else is causing the problem. Backfiring is usually a symptom of a timing issue, but not always. As Rowefast said maybe something in the distributor. 351M was a great engine that would go many miles if properly serviced. The only thing bad I remember about them was that they used lots of fuel. Keep us posted on what the repair ends up being.

Your Answer


Looking for a Used F-150 in your area?

CarGurus has 199,176 nationwide F-150 listings starting at $1,300.


Ford F-150 Experts

  • #1
  • #2
  • #3
View All

Related Models For Sale

Used Chevrolet Silverado 1500
2,290 Great Deals out of 169,689 listings starting at $1,000
Used GMC Sierra 1500
1,014 Great Deals out of 66,367 listings starting at $2,495
Used Ford F-250 Super Duty
329 Great Deals out of 45,898 listings starting at $1,700
Used Dodge Ram 1500
367 Great Deals out of 10,821 listings starting at $1,500
Used Toyota Tundra
495 Great Deals out of 33,973 listings starting at $2,000
Used Toyota Tacoma
584 Great Deals out of 45,038 listings starting at $1,790
Used Ram 1500
1,016 Great Deals out of 110,728 listings starting at $6,900
Used Ford Mustang
595 Great Deals out of 36,389 listings starting at $899
Used Ford F-250
465 listings starting at $2,995
Used Nissan Titan
211 Great Deals out of 20,825 listings starting at $3,390
Used Chevrolet Colorado
275 Great Deals out of 34,531 listings starting at $1,900
Used Ford F-350 Super Duty
330 Great Deals out of 25,593 listings starting at $3,700
Used Chevrolet Silverado 2500HD
335 Great Deals out of 30,637 listings starting at $3,500
Used Chevrolet Tahoe
729 Great Deals out of 41,714 listings starting at $1,995
Used Ford Explorer
930 Great Deals out of 69,576 listings starting at $1,495

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.