Any creditor can take adverse action and it's not just about score but all the data in the report. You're not free to do whatever with your credit after getting approved with no consequences. The data in your reports always matter to your creditors which is why the routinely review reports with soft pulls.
As others have stated. we can't tell you what AmEx will do in your case but the $1K limit already indicates that they have concerns with your credit.
SumTingWongFoo wrote:Now that Experian will, how will this effect my current open credit cards, including my AMEX, since AMEX pulled from my Experian before the collections was added to that report?
Different creditors have different risk tolerance thresholds. It's possible that all may take action against you. It's possible that some may and some may not. It's possible that none may. We have no idea. We don't know the specifics for your creditors and we don't know all the details regarding your credit profile.
If you have issues that you can address then definitely get to work on them. Do whatever it takes to avoid derogs going forward. They tend to have significant impact and can stick around for a long time if you are unable to remove them.