I'm getting new tires for my car, a 02 v6 Im switching from the 235/55 to a 245/50 tire like the z. The tire is smaller,25.7compared to 26.1
It will change spedo by 1 mph,did gm do anything to compensate between models?

 

should be able to adjust using a handheld tuner.

 

You're not going to notice a 1 mph difference, it's not even worth the effort to fart around with it. Heck, some cars have been off more than that from the factory. For all you know, that 1 mph could bring your car closer to spec. lol

 

yup my 99 is off like 4 miles per hour depending on the grade an my foot to the pedal no big deal

 

You mean like at a green light where the speedo is reading 80 and the car is barely moving? lol

 

Thanks,I'm total newbie when comes to computer cars, I get it,but don't know how to work on them,I will learn.
A handheld programmer,never used,is that a job a gm tech would handle? I won't bother like said since it's only 1 mph,I wasn't sure if it would mess with any other things,like abs and what not.
I bought a Haynes book for it,ben reading that. My next project is replace the brake fluid,it's old and black,I don't have traction control so says I can do it at home,any tips before I head in?n

 

Over did it,fluid isn't black it's old and has a blackish tint to it ,needs changed .

 

go here and download the factory service/shop manual, 2000 will work fine for the 02 https://www.mediafire.com/?40mfgeoe4ctti

 

Thanks

 

just city traffick I have not gps it ,just feel like it in the 3800,the 3800 does not go over 70mph ,I just choose to keep it in the slow lane on highways though I may have been to 80 a time or 2,now the 406 125 felt great with more pedal ,but as I get older I just relize going fast cost money sooner or later