idles around 800 rpms, when i put the car in drive my rpms drop to about 650

[razey]

hey guys,

I have a 98 spyder auto, my car idles around 800 rpms, when i put the car in drive my rpms drop to about 650 and the car starts to idle a little rough. I just got it shipped to PR and had to swap out the battery because the moving company left a light on in my car. Could my alternator be going and causing this to happen?

 

[viprez586]

More then likely no.

1st and foremost Boost leak test.

Check your base ignition timing. Once thats all good and set adjust your BISS.