The service engine soon light is on..how do you check the codes?

Yep, I did Google it, I found that information but I don't know what it all means...is this something that I can replace or do I need to take it to a mechanic to have the knock sensor replaced?

  If you are not sure what they are talking about then I would suggest having someone that does have a look. It may be a lot of things....but most likely I would suspect the the module is shot.... But that is just a guess.

Thanks for all of your help.

The knock sensor on your 85 is the same place as on my 85 right in front of the starter behind the exhaust manifold it can be reached if you lift the car on the passenger side about a foot with the wheels turned to the left. unplug put a 7/8 s wrench on it to turn it out, it sould take a bit of muscle it will be tight. put the new one in and torque it to spec. if no torque wrench if you hold a ten pound weight in your hand for five minutes then tighten it to the feeling you have in your arm it should be fine. very easy to change as long as you can get under the car. good luck. it took me fifteen seconds to change mine Friday and have not had a code since. now according to the manual it may come on three times while it learns what a knock is again. mine did. then just make sure you keep high octane fuel higher than92 octane and you should never see the code again. Hope this helps. sensor cost me 42.00 pretty salty for what it is. but it does have a function. Happy Vetting my friend!

Thanks for all of your help.  I have enough info when I take it to the shop.  The guys at the shop are very reasonable and I can usually tell them what I need and they'll take care of it.  I want be doing this one myself....