altitude or air density

[1iwilly]

that's what i'm trying to find out what is a normal reading and what is acceptable .but the bad thing after every adjustment you have to drive over 100 miles for then the computer make the final adaptation for you then to see if the changes you made work.thanks once again to those that have reply.hopefully this weekend i'll do another trip to daytona beach and back

Originally Posted by admranger

What's the acceptable range of fuel trims? This could all be normal...or not.

I'm with bcred here. MAF or pre-cat O2 sensor(s) if it is a problem. Or perhaps you were getting air leakage and you resolved that by turning screws.

For the record, the partial pressure of oxygen decreases at altitude. Nothing gets 'thinner' at altitude with the possible exception of the ski "bunny" at the bar after your 9th beer.