High end power loss

Welcome to 2CarPros.

This is a tough one because the ECM reacts to other signals. Basically, the engine operating conditions (speed, load, warm-up condition, etc.) are detected by the various sensors. Based on these sensor signals and the ignition timing data, signals to interrupt the primary current are sent to the ECM. The ignition coil is activated, and timing is controlled.

Now, could it be the ECM, yes, but it could also be many other things. Since you have a live data scanner, pay attention to the throttle position sensor, if timing is retarded due to shift patterns, and so on.

To add insult to injury, the transmission control module can also be at fault. The ECM uses torque reduction signal from TCM (transmission control module) to reduce the shift shock by controlling ignition timing. If duty ratio is approximately 9%, ECM advances ignition timing to approximately 20 degrees and If duty ratio is approximately 90%, ECM retards ignition timing to approx. 20 degrees.

Are you certain there are no trouble codes stored in the system? For example, P1765. That is the torque reduction code. Something could be going haywire between the TCM and ECM.

God, I miss the old days. LOL

Let me know.

Joe

Thank you for the reply. I should have mentioned that the TPS was the first thing I thought of and changing it did not help. And there are no codes stored. Also the car has a manual transmission. I think the codes you mentioned only apply to an automatic.

Welcome back:

You are correct about the code. I'm not sure why I added it. As far as the problem, have you checked to see if there is a blockage in the catalytic converter? A partially plugged converter will cause a power loss.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter
Let me know.

Joe

Yes, it could be a blocked catalytic converter, but would that produce the timing behavior we have here?

Welcome back:

If there is too much back pressure, it could cause issues even with the timing.