Rough Running 89 Bronco
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Rough Running 89 Bronco
I have a 1989 Bronco with a 1997 4.0 litre engine.
When I start the engine it idles well for a few seconds and then idles very rough or stalls out. when I step on the accelerator the engine will not rev high..it revy up a bit to about 3-4 000 rpm and then max's out. That is with foot to floor. I have replaced the 02 sensor. I am thinking a fuel problem? I was just driving down the road and all was fine and then all of a sudden she would hardly accelerate.
When I start the engine it idles well for a few seconds and then idles very rough or stalls out. when I step on the accelerator the engine will not rev high..it revy up a bit to about 3-4 000 rpm and then max's out. That is with foot to floor. I have replaced the 02 sensor. I am thinking a fuel problem? I was just driving down the road and all was fine and then all of a sudden she would hardly accelerate.
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Joined: Oct 2003
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From: Connecticut
Welcome to FTE savvy5473,
The 89' bronco has a EEC-IV computer system in it + the 97' uses a OBD-II computer system to power it.
I'd say this is the conflicting problem.
Try pulling the computer codes + see what kind of readings you end up with.
I have a 1989 Bronco with a 1997 4.0 litre engine.
When I start the engine it idles well for a few seconds and then idles very rough or stalls out. when I step on the accelerator the engine will not rev high..it revy up a bit to about 3-4 000 rpm and then max's out. That is with foot to floor. I have replaced the 02 sensor. I am thinking a fuel problem? I was just driving down the road and all was fine and then all of a sudden she would hardly accelerate.
When I start the engine it idles well for a few seconds and then idles very rough or stalls out. when I step on the accelerator the engine will not rev high..it revy up a bit to about 3-4 000 rpm and then max's out. That is with foot to floor. I have replaced the 02 sensor. I am thinking a fuel problem? I was just driving down the road and all was fine and then all of a sudden she would hardly accelerate.
I'd say this is the conflicting problem.
Try pulling the computer codes + see what kind of readings you end up with.
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I checked the fuel pressure and it is 40 psi which is the proper pressure. I pulled the trouble codes and they are
22 Manifold Absolute Pressure Sensor
45 Secondary Air Upstream
66 Mass Air Flow Sensor.
I may have caused the 66 as I unplugged the Mass Air Flow while the engine was running.
Now I am thinking the MAP sensor??
22 Manifold Absolute Pressure Sensor
45 Secondary Air Upstream
66 Mass Air Flow Sensor.
I may have caused the 66 as I unplugged the Mass Air Flow while the engine was running.
Now I am thinking the MAP sensor??
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I replaced the MAP Sensor. It will idle better now but still will not rev high when stepping on it. What is very odd it that when you first start it, it runs fine and revs perfect for the first 5 seconds and then goes bad from there.
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