89-92 2.9l has a rough idle and low power issue.

[91ranger.danger]

I have a 91 2.9l v6 4x4. When I drive about 5 miles, my truck will start to run rough and have low power in high rpms. It will start lugging at idle, when I shift the rpm drops a lot, and then the truck bucks when I let out on the clutch (in gear). When I get to about 1800-2000 rpm, the truck sounds like it continues to climb rpm but doesn't want to spin the wheels. The engine light turns on, which tells me that the computer recognizes that there is a problem. When the problem occurs, you can turn the truck off and start it back up immediately and drive it another 5 miles perfectly.

My dad and I have run code tests and have only seen code 63, the TPS error. We have replaced the TPS and the MAP sensors, and we have removed the o2 sensor and the ECM computer. We don't think that it is a vacuum leak, because we don't hear a whistling noise. We think it is either electrical or a computer problem, since the problem can fix itself with simple restart.


What are other options that could be causing the problem?
Can we DIY test the ECM and how? Who can test the ECM?

 

[franklin2]

Once you changed the TPS sensor and unplugged the battery for a minute or so, did that code come back after driving it?

 

[91ranger.danger]

Once you changed the TPS sensor and unplugged the battery for a minute or so, did that code come back after driving it?

Now that you mention it, we never did wipe the code memory from the truck. But the problem still occurred after we replaced it.

 

[rusty ol ranger]

Now that you mention it, we never did wipe the code memory from the truck. But the problem still occurred after we replaced it.

Try wiping the codes and see what comes back