We just drove our 98 Blazer 4x4 from 7400 ft elev to almost sea level. We got here today. The truck runs great. 21 mpg on the road. Got gas today then went out tonight. After about a 25 mile drive with stops I got about a mile from home & I see the CEL is on. So I got home & plugged in my scan tool & a PO171 showed up. I cleared it & started it & it was off.
Any thoughts? Could it be the change in elevation just not reset yet to the lower elevation?
I will drive it tomorrow & see if it comes back on.
It has a new pump, filter, plugs, cap & rotor, & fuel pressure regulator, ALL AC DELCO or DELPHI parts.
Thanks,

 

https://blazerforum.com/forum/diagno...plained-35154/ After reading this I would think yes older sensors exposed to changing barometric pressures could set this code.

 

Thanks for your response. I kind of wondered if that wasn't a possibility. I guess driving it today will tell.
I'll update tonight.
Thanks.

 

UPDATE:::

Ran the truck all day about 54 miles of stop & go city traffic, No further CEL.

 

Before you get too excited, make sure all of the monitors have run and completed their tests. Your scan tool should be able to tell you if they are all complete. It will be listed under a menu named "I/M Readiness" or "Monitor Status". If all of the monitors are not complete, perform the General Motors Driving Cycle This will force them all to run and complete... if you do the drive cycle correctly You don't need to do the steps in order, but you do need to execute each one exactly as written.

 

Yea, I drove it another 150 miles yesterday both freeway & town & have had no further issues with CEL. So I'm not going to worry about it unless it comes back soon. This Blazer has been a basket of worms from the get go. I'm at a point of cutting my losses & just driving it until it quits. I'm looking for another vehicle a Ford Ranger 4x4 or Dakota 4x4. I wish I would of never sold my 97 Blazer 4x4. This 98 is a POS.