Engine will sometimes not rev

[Rotary91]

Originally Posted by NoDOHC

It could be an intermittent vacuum leak for the rough idle, but if it is coupled with the inability to rev, it almost has to be limp mode.

This is puzzling.

I tried unplugging the TPS on my '91 and revving the engine and it revs just fine. I also tried without the MAP sensor - same results. It almost has to be an Oil Metering Pump feedback issue (I don't remember what all codes can set the limp home mode).

Did shutting the key off and turning it back on fix the issue this time too?

I wonder if the CEL is not setting because the fault is immediately clearing, but the limp mode is latched on.

Key method seemed to fix it again. Is there any way to check if its the OMP while the problem is happening? Check wires for resistance and continuity sort of thing.