I pulled stored codes today because my '93 5.0 turns on the CEL after fifteen minutes or so and resets when I turn the engine off. I got 11 and 41 codes, 41 being O2 sensor reporting always lean.
I'm assuming that the first thing I want to try is to replace the sensor, but my main question is if I will hurt the truck in any way if I wait until after an upcoming 600 mile road trip to change the sensor? Preparing for the trip I don't have a lot of extra time to run down the part and change it out, but if I stand a chance of damage I will have to make time to do it.

Thoughts??

BTW, a little history. I bought it a month or so ago, failed the smog test because it was too rich (no CEL on then) so I replaced the air filter, cleaned the intake, and replaced the water pump and thermostat due to it having fallen apart, not allowing the engine to come up to temp. After those changes it sailed right through the smog test but soon after started with the CEL thing. I'm wondering if the cleaning of the intake may have fouled the O2 sensor?
Thanks.

 

the truck running lean can mess up the cat, but that usually happens after a long time (10k+ miles minimum id imagine) people say there is stuff that will foul the sensors (i imagine there really are) but iv never heard of someone doing something, then the next day a sensor fails because of it lol. the only bad thing i can see happening in 600 miles is bad fuel mileage.

 

Thanks.
Ended up not doing the trip, but another thing that is concerning me is that there is a slight squeel when it's under light to moderate acceleration from a stop. Sounds like a baloon being squeeked by squeezing out a little air. I wonder if that could have anything to do with my code 41, maybe a vacuum leak? Has new serpantine belt, water pump, t-stat, and has not changed.

 

only thing i can think of is a wheel baring or bad u joint. but id rather have someone else jump in on this one, im not very familiar with vacuum issues, i just know iv never heard of one squeaking like that before.

 

I can change volume (but not tone) or eliminate it by changing throttle position if that helps any. Take my foot off the gas or floor it and it goes away, I can't hear anything at speed.
It just seems to last the few seconds it takes to get to speed around town.

 

Bump
C'mon folks, somebody out there has seen this before.

 

OK, here's an update. A week or os ago I replaced the O2 sensor and the truck has been running great ever since. I've driven a little over a thousand miles and the mileage went from a dissapointing 12-14 to 17-19 after the first tank of gas.
The squeel is still there, but with that kind of MPG who cares??