Need Mech help

[deermount]

i have a 93 buick centruy did a full tune up and all the sudden the car runs rough have to pump the gas to drive it idles smooth and the a/c gets cold untill you idle up the rpms did a code check on ut says it a DTC 28 3rd gear switch have no idea what that is looked up on google and said what ever the 3rd gear switch is will make the car run slugish and afect the a/c but did not say what to look or do for it Thanks

[Gummi Bear]

Try disconnecting the battery (both terminals) for a couple hours.

This will allow the computer to blank out it's memory (don't worry, the programming is still there) and allow it to "learn" with the new tune up.


All you need is ignorance and confidence, and the success is sure. - Mark Twain