Please help with random backfire
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Junior Member
Joined: Jun 2003
Posts: 3
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From: JAX
Please help with random backfire
I have a '99 F-150 w/4.6, auto, 67K miles. Yesterday after filling the fuel tank and adding 2 bottles of Techron, I noticed a random pop or backfire when traveling 70-75mph.
I have never had this happen before.
The CE light was on a few weeks ago and the code was slow upstream O2. The light went out and I haven't taken time to replace the sensor yet. I have a K&N in the stock air box but otherwise stock.
After getting off the highway and driving city speeds it never popped or backfired again.
Please help me diagnose this. I searched archive but didn't find anything that helped.
I have never had this happen before.
The CE light was on a few weeks ago and the code was slow upstream O2. The light went out and I haven't taken time to replace the sensor yet. I have a K&N in the stock air box but otherwise stock.
After getting off the highway and driving city speeds it never popped or backfired again.
Please help me diagnose this. I searched archive but didn't find anything that helped.
Senior Member
Joined: Oct 2003
Posts: 612
Likes: 0
From: Texass
My first step would be to get that sensor replaced.
It's not "uncommon" to have some crud come loose and foul a plug if it has be a while since the last time you ran a cleaner through it. Run the rest of the tank out and fill up with some clean fuel.
Might want to have a look at the plugs too. If one is fouled, it wont clean itself, you'll have to replace it.
It's not "uncommon" to have some crud come loose and foul a plug if it has be a while since the last time you ran a cleaner through it. Run the rest of the tank out and fill up with some clean fuel.
Might want to have a look at the plugs too. If one is fouled, it wont clean itself, you'll have to replace it.