Engine backfiring

2004 FORD F-150

299,123 MILES • 5.4L • V8 • 2WD • AUTOMATIC

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My truck is backfiring very bad so I took the catalytic converters off because I thought it was that. The converters were very dirty and the honeycomb things were broke. so after I took that off I started the truck and it was still popping very bad. I’ve changed sensors, spark plugs, coils and boots, VVT solenoids, oil change, and it still pops I’m not sure what else I should check because no check engine light is on.

Mar 19, 2021 at 6:33 PM

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JACOBANDNICKOLAS

AUTOMOTIVE REPAIR CONTRIBUTOR
110,190 POSTS

Hi,

The most common cause of a backfire is a rich fuel mixture. However, with 300,000 miles, it may simply have a burnt valve or low compression.

Take a look through this link first:

https://www.2carpros.com/articles/engine-backfires-while-running

If that is not helpful, we need to check engine compression. Here is a link that shows how it is done:

https://www.2carpros.com/articles/how-to-test-engine-compression

The pics below show the directions specific to your vehicle and the acceptable ranges. Take a look at the pics below.

Let me know if this helps or if you have other questions.

Joe

Images (Click to enlarge)

Mar 19, 2021 at 7:56 PM