This is topic Car is backfiring around 4000rpms.. in forum Tech Talk at Northern California Ford Owners  .


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Posted by AL STOCK (Member # 1852) on :
 
So everytime i punch it hard the car backfires and loses power around 4000rpms then regains power around 4800rpms... When i say loses power, it feels like the car wants to move but the backfire is holding it back..Backfires about 2-3 times then starts gaining power...This happens when car is warmed up but hardly happens in cold conditions..

What can this be? Spark Plugs? Air Filter? Exhuast?

Thanks
David
 

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Posted by 2stangs69-91 (Member # 1951) on :
 
my guess would be wires,also plugs.
 

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Posted by FasterDamnit (Member # 442) on :
 
WHen your motor is cold you are running in open loop- not looking at O2 sensors. Once warmed up you go into closed loop. WOT also goes into open loop, but I believe the fuel tables are different between cold operation and normal operating temp. Sure your fuel pressure is right?
 

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Posted by Black94 5.0 (Member # 655) on :
 
If its an exhaust backfire, check for an exhaust leak or a faulty air injection diverter valve...
 

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Posted by AL STOCK (Member # 1852) on :
 
Damm i hate exhuast leaks! Im gonna get underneath and retighten every exhuast bolt..

Also gonna throw in new spark plugs since my wires are still new.. My plugs were last changed about 8K miles ago -

Yeah my fuel pressure is right. Still stock lol
 

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