can anyone help?

ok, here is my problem on my 96 3.8. my service engine light came on. it was a code for #5 cylinder misfiring. it stumbles on acceleration until it reaches about 35 mph. when the car sits overnight without running and I start it in the morning, it runs fine for about 5 to ten minutes until it is warmed up it also trips the abs warning light when it warms up. can anyone help? thanks!

Start with the ignition system for the misfire. So check the wire and plug thuroughly. Did this jsut randomly start doing this, or was some work performed, ie tune-up, done that may have caused it?

I don't think the ABS is related either. Chances there are a dirty sensor or relucter ring.

now the engine backfires on acceleration in the engine compartment. possible burnt valve? some kind of gasket leak?

What have you looked into (checked) ?