suddenchance
New member
Hey everyone,
I have a 1988 Bronco with a 5.0 engine that's experiencing some issues. It’s backfiring through the intake and missing, making it feel like it's only running on six cylinders. The engine is new and was tested before installation, showing positive results. The ECU is also new and has been tested.
The engine starts easily, but after 2-3 minutes of running, it starts to miss, and I hear backfiring at around 1200 RPM and above and the check engine light stays on. There are no vacuum leaks, and the fuel pressure at the rail is holding steady at 30-33 psi. I’ve replaced the O2 sensor and changed the throttle body, the idle air control (IAC) valve, and the manifold absolute pressure (MAP) sensor.
After running the diagnostic codes, I found that both the IAC and MAP sensors are out of range. I tested the voltage on the MAP sensor, and it read correctly. The engine is running rich, and I’ve also installed new injectors, spark plugs, and plug wires. In fact, every component on the truck has been replaced. The truck is displaying the same symptoms it had with the old engine, so I know the issue isn't due to the new one.
It's acting exactly like the timing is off but the timing is set perfect and the firing order is also correct.
Any ideas or suggestions would be greatly appreciated!
I have a 1988 Bronco with a 5.0 engine that's experiencing some issues. It’s backfiring through the intake and missing, making it feel like it's only running on six cylinders. The engine is new and was tested before installation, showing positive results. The ECU is also new and has been tested.
The engine starts easily, but after 2-3 minutes of running, it starts to miss, and I hear backfiring at around 1200 RPM and above and the check engine light stays on. There are no vacuum leaks, and the fuel pressure at the rail is holding steady at 30-33 psi. I’ve replaced the O2 sensor and changed the throttle body, the idle air control (IAC) valve, and the manifold absolute pressure (MAP) sensor.
After running the diagnostic codes, I found that both the IAC and MAP sensors are out of range. I tested the voltage on the MAP sensor, and it read correctly. The engine is running rich, and I’ve also installed new injectors, spark plugs, and plug wires. In fact, every component on the truck has been replaced. The truck is displaying the same symptoms it had with the old engine, so I know the issue isn't due to the new one.
It's acting exactly like the timing is off but the timing is set perfect and the firing order is also correct.
Any ideas or suggestions would be greatly appreciated!
