Welcome Visitor! Please take a few seconds and Thrashingrage
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- Joined
- Aug 3, 2012
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- 30
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- Vehicle Year
- 1990
- Make / Model
- Ford
- Transmission
- Manual
Hi guys,
I have attempted to do my homework before posting this. Looked up some other threads and none of them seem to directly address this issue. I have a '90 Bronco II with a 2.9 in it. I have been occasionally hearing a backfire-esque noise at high speed. It happens intermittently, only in 5th gear, and always at or above 55 mph. It sounds almost like a backfire but not very loud, closer to a popping or coughing noise. I'm almost positive that it's coming from the cats. It only happens occasionally and doesn't seem to have any effects on performance when it does. I just drove about 250 miles from my home in Colorado to Northern New Mexico, and while I'm here I drive an average of about 30 miles per day on the highway (45-60 mph). The Little Bronco has done fine. I've heard the noise a few times on the trip, but it never seems to be detrimental. The worst case of it happened several times in the span of ten or so seconds one time at about 65 mph. I have replaced O2 sensor, had a Flowmaster put on, and have new spark plugs and ignition wires, as well as a k&n intake, which I plan to eventually replace with the stock airbox. It's also worth noting that the timing is set a 12* below tdc running 89. If anyone has any ideas as far as what could cause this noise, I'd appreciate any insight you all can give. Thanks in advance for any help and/or advice.
Josh
I have attempted to do my homework before posting this. Looked up some other threads and none of them seem to directly address this issue. I have a '90 Bronco II with a 2.9 in it. I have been occasionally hearing a backfire-esque noise at high speed. It happens intermittently, only in 5th gear, and always at or above 55 mph. It sounds almost like a backfire but not very loud, closer to a popping or coughing noise. I'm almost positive that it's coming from the cats. It only happens occasionally and doesn't seem to have any effects on performance when it does. I just drove about 250 miles from my home in Colorado to Northern New Mexico, and while I'm here I drive an average of about 30 miles per day on the highway (45-60 mph). The Little Bronco has done fine. I've heard the noise a few times on the trip, but it never seems to be detrimental. The worst case of it happened several times in the span of ten or so seconds one time at about 65 mph. I have replaced O2 sensor, had a Flowmaster put on, and have new spark plugs and ignition wires, as well as a k&n intake, which I plan to eventually replace with the stock airbox. It's also worth noting that the timing is set a 12* below tdc running 89. If anyone has any ideas as far as what could cause this noise, I'd appreciate any insight you all can give. Thanks in advance for any help and/or advice.
Josh
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