Just picked up a 2003 Bonneville SLE (134,000 miles) and after finding this board seem like I am part of a new family. This board is incredible. Here are the few issues I have discovered and what I planning to do:

Check gas cap code - I will probably buy new cap and clean filler neck very good. Should make the error go away.
Whining noise under hood - Appears to be coming from idler pulley and will replace the pulley
No cabin air filiter - Put in one.
Previous owner (good guy) states it uses a little oil. Will change PCV valve. He may not have done this.
Oil presure gauge pegged at 120 - I will replace oil pressure sending unit.
I can feel a little clunk in the steering system. Not bad. Plan to try and lube but not quite sure from other posts how to do this.

I am a little concerned about all the talk about intake manifold gaskets. Previous owner never had issues with this. Will probaly just let it ride unless I get advice that states otherwise.

Thanks again for the great forum.

This car is in great shape and I hope to keep it running for many more years. Thanks for all the advice

Hey Mark!

Glad you found us. We can help you keep that Bonnie on the road for years to come.

Keep an eye on the coolant level. If you find yourself adding to it and notice a sweet odor in the exhaust, you're nearing the time for a gasket replacement.

Sounds like you got most things covered. Check here for the clunk, https://www.gmforum.com/mechanical-134/intermediate-steering-shaft-repair-replacement-285548/

We should be able to help fix all your problems.

Welcome! You will get all your problems solved here! Great group of experience and smarts!

Welcome to the forum. It sounds like you have a good start on getting your Bonne running perfect again. Keep us posted on your progress

Hey welcome to the forums hope u enjoy yourself here