89 Van occasional engine light with codes 25,26,51

Three times now in the last 200 miles my check engine light has come on for about 30 seconds then turned off. Each time was when I was moving at a constant speed and I could feel no difference in the way it ran when the light switched on or off. It feels the same it always has. It might be burning a bit more gas than before but that could just be my imagination.

I'm not quite sure where to start here. As far as I know none of the sensors have been changed in at least the last 80k miles. It currently has 240k miles on the original engine.

Any suggestions?

My first reaction would be to change the front O2 sensor and clear the codes.

Gwen

What Llama said should take care of 25 & 26. Assuming you've cleared the codes & they've come back, I'd also clean the throttle body and replace the TPS. That should take care of code #51. Tim

Thanks! I will swap out those sensors and see if that does it. Hopefully the O2 sensor will come off without too much of a fight.