How do you know if someone put a bomb on your car?

Car bombings, outside civil unrest areas, are extremely rare. The first source lists one in the entire world last year, in Malta. The second source has the details. In Arizona there was one in Phoenix in 1974 that assassinated an investigative reporter and it brought dozens of investigative reporters to Phoenix and resulted in at least two books.

I am more interested in your worry about enemies trying to assassinate you. Your level of concern ("consuming my life severely") and inability to identify who would be so motivated against you suggests a clinical problem with paranoia. Your doctor can probably go a long way to returning your life to you. You don't write like a severe paranoid schizophrenic - I have seen several of those here with much more specific fears - so I think you can see a great improvement. Good luck!

Stop driving!

Why would anyone go to that much trouble? It's not like they can go to Pep Boys and read: "Bombs - Aisle 2A."

Nice troll. Caltech and MIT needs brilliant minds like you. Do not waste it trolling.

The more proactive bomber today will stand by at some distance and blow you up by remote control radio.
Maybe when you just take off or maybe they will follow you in a 1939 sedan with the transmitter, waiting to blow you up in time with the 12 Noon railroad whistle.

use a mirror to look under your car. also you can look for fingerprints on the hood of your car's engine

If your car explodes, then a bomb was put in it.

Call ATF, have them bring puppy with good nose for nitrates. Depending on ACTUAL CAR, ACTUAL ENEMY might find a limpet with cord wrapped around axle, might find spark plug cable has a jumper to small box under drivers seat area. Jumper wire to a spark plug dropped inside gas tank filler neck may be done on some cars without damaging hood, be unnoticable until gas tank goes 'boom/woosh/sizzle'.

https://www.youtube.com/watch?v=aLhWzMOccTg