I just changed the oxygen sensor on my 1988 22 RE truck. Now the check engine light comes on only when I get on the highway, after about a mile just as I pass IHOP at about 60 MPH. Is this pancake related, or maybe O2 sensor related? The light stays on until I shut off the truck. Then I can start it right up, no light until I go fast again. Strange.

 

Try stoping for pancakes, couldn't hurt anything.
What code is the truck throwing?

 

You did use a Denso sensor as a replacement? Bosch or other brands is not recommended and likely to toss a CEL.

 

I'll check for a code. This is the first fuel injected rig I've had, so I'm not used to checking the computer. Pancakes seem like a good idea right now.

 

OK, it took me many months to figure out how to check my check engine light, but I finally got a code 26: engine too rich, or possibly a starter injector issue (I think it's the too rich one- a problem I don't share, personally). Any thoughts, ideas or comments?

 

Have you tested the cold start injector?

 

Not yet.

 

OK I just checked it. The switch is reading like it's grounded out. No resistance, bad? at about 100 F.

 

Update: I checked again with a better meter, and it looks like the switch isn't the problem. I haven't pulled the injector yet to see if it's working, but the exhaust definitely smells too rich.

 

I have heard of the running rich condition and wondering what is causing it. Looking forward to seeing what it could be.

 

I wasn't really sure about the ohmmeter test, so I got a new cold injector temperature switch used on ebay. So far it seems better. I have to drive past IHOP to really test it out.

 

Since it started when you changed the O2 that could be a culprit. Did you put a Denso in there or something else? I learned my lesson with Bosch years ago when I immediately got codes upon installing a new one. Denso only, plus it's cheaper!