i am going to go from my stock wheels and tires 235-16 to custom painted 10 spoke ss rims with 275's. my question is this with this wheel change will i need to program my pcm or not. i am going to get it programed when i do a gear change but that will not be until next spring.
thanks

 

The 235/55-16 has an outside diameter of about 26.18" That's what your PCM will have programmed in it. The 275/40-17 has an outside diameter of 25.65". You will have to change the tire diameter in the PCM for the speedo to be correct.

If its just a while 'til you get the programming done, there's not a lot of error. The speedo will be reading about 2% faster than the actual road speed. At a true 70mph its going to be showing 71.4MPH. And when you drive an actual 1,000miles, the odometer will show 1,020 miles.