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

[Reducto]

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?

[llamavan]

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

Gwen

[timsrv]

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

[Reducto]

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.