Will an intermittent OVP activate the check engine light?
The fact that the check engine light goes on while this is happening seems to be an important data point. Or will the light go on with a very low idle, while it is hesitating (it also illuminates at speed during the hesitation)?

I was also thinking of swapping the fuel pump relay. If I understand correctly, this model (1989) also has the mass air sensor relay bundled with the fuel pump relay?

Thanks for any input,
Gregg