I recently installed 4 speakers, a deck, an amp, and subs into my truck. About 8 hours after I installed them the speakers suddenly went down, the subs kept thumping, but the speakers are down.

Recheck your connections from deck to "non-sub" speakers. Are you using an adapter from deck to vehicle wiring harness OR are all wires individually connected?

The amp is going into protect on the two channels powering the speakers. Turn down the gain on those two channels. You also may want to consider crossing over the speakers a little higher than they are now.

The rating on those speakers are way too high. 6.5's and 6x9's will take 50-100 clean watts tops before they start to break up.

The best solution to get it perfect is....unplug the subs. Turn the gain on the speaker channels all the way down. Then turn up the deck 80% as high as it will go. Play a song. Then increase the gain on the amp until the speakers are as load as they go without distortion. Shut off the car, replugg in the subs and do the same thing. Gain on sub channels all the way down, deck then to 80%, find a bass heavy song, then turn gain up until subs become distorted. If you do this procedure your speakers and subs will be "gain matched" to the proper levels.

Good Luck

No only 2 speakers with the other channel bridged.

i had to buy a complete amp and replace the old

sounds like you blew some fuses replace them. then reconnect stock wiring. the get after market deck, amp, and wiring that in it's color coded so it no that hard to do.that 10 inch pa speaker pulls a lot power plus it 8 ohm impudence. your going to need at least a 200 watt amp.bridgeable.
or single channel.

connect the speake(sub) directly to the stereo(just use one of the rear 6x9 speaker wire to test the sub and make sure it's not the amp. if it does not work, it's the sub

Check ALL the ground wires. Did you use a fuse block power source for the subs?

Any sub can be blown in 30sec if given bad clipped power, so just measure them with a multimeter and see if the coils still have resistance. Throw away the test light and only use a multimeter.

that sounds like the amp might have a bad ground.

Could be your speakers are breaking down inside and shorting out. Measure the ohms of the speakere with them unhooked form the amp. They should be about what the manufacturor rated them at. (useually 4 ohms). If they are failing, the number will be lower. They may also short when power is applied- and that wont show with the meter test.

Try different subs.