96 2.5TL 105,000 miles

When I start the car after going shopping or picking up something from the store, I start the car, but it cranks for a good 5-10 seconds.... at this point it seems like the car might not start but at the last moments starts up. It seems as if the car is struggling to start up.

This does not happen when I first start the car in the morning. It only happens when the car has been driven and the car is already warmed up.

This only happens on a few occasions, but I seem to be noticing it alot more now.
Also, when the car is idle around 1000rpm, there's slight vibration i can feel, but not sure what it is.

I already changed the battery and replaced sparks, wires, and caps, but didn't seem to help the problems. HELP!