backfire through carburetor

Have you checked to make sure all the spark plug wires are routed correctly? That could cause your issue if there not routed correctly.

Yes, used a diagram found on internet to connect plug wires. Could bad temperature sensors cause this problem?

No, a bad temperature sensor is not going to cause a back fire through the carburetor that is miss routed spark plug wires or it is out of time or the engine is really flooding out.

So what happened that lead up to these events before you replaced all these parts? tell me a story.

I parked it on a Monday night and then on Tuesday morning it would not start all it did was crank but not start. so i check for fuel to carburetor and i could see it spray into carburetor but not start. so i checked for fire in which there was no fire coming to plugs so i changed coil pack and still no spark. then i removed distributor cap and found rotor was melted on the side so i changed cap and rotor. That is when i tried starting it again and car started sputtering and when i press gas pedal fire shoots up from carburetor. I thought my friend had put the new ICM in, but i found the new ICM in my toolbox. Do you think the old ICM could cause this problem?

No, you would just have a spark issue a lack of or intermittent spark if it ran fine before. I highly suspect something is up with the spark plug wire routing. Sounds like the cap and the rotor was the original issue with the spark issues. i know you said you checked the routing and you said it was fine, but I have been told that before and it ended up being what I suggested that was already checked.

Okay, do you have correct firing order?

I posted the firing order and spark plug routing on the distributor cap.

So number one wire goes to the cap point front closest to drivers side and number three goes front side closest to passenger side.

Yeah one, three, four, two, is that what you have?

I think that is the way i have it, but it is after ten at night so i will have to double check tomorrow after work around 6:00 pm and then relay my findings to you. Thanks for all your help, tolerance and patience to a shade-tree guy.

You are welcome. that is what we are here for. talk to you soon.

Good afternoon, i checked the plug wires and yes they are correct. i am going to get new plugs and wires later this evening.

Okay let us know what happens.

Changed plugs and wires still doing the same

It sound like you may have a camshaft or valve issue. Can you do a compression test to see whats going on? Here is a guide to help you

https://www.2carpros.com/articles/how-to-test-engine-compression

Please let us know what happens so it will help others.

Cheers, Ken