Fried radio.....I think

I'm sure you have your antenna, and your mic hooked up?
Do you have a pa/cb switch? Is it on cb?

 

double ck all your connections, if you are picking up interference from engine then I doubt that the radio is fried. turn your RF gain to max and turn your squelch all the way down so that you are not muting any signal noise. I had to replace my coax today as it had a break in the wire someplace and would get reception or transmit intermittently. the new coax took care of my problem, which was basically similar to your problem, sometimes I could get out or receive but most time it was quiet until the break in the coax would touch or make contact. another option to correct the engine noise is to install a filter which wires into the main power source, but I doubt this will fix the problem you have described , I think it is more than likely the coax is bad. If you do replace the coax get a quality one thats at least 18 feet.
good luck

 

I've got two cobra 29's. One is a standard ltd. The other is a nwst. With the automatic noise limiter turned on, the 'noise' should be knocked down quite a bit.
I'm not familiar with a Lil Will antenna.
Your most recent post says it would get loud, then quiet, then statiky.
Reminds me of when my microphone shorted out. I was talking to a friend of mine as we were driving down the interstate. I began to realize that when I lifted the mic to speak, the sound on the radio would pick up, sound better. When I put it down, the sound on the radio would almost cut completely out. So, I started wiggling the mic cord from one end to the other. Just before the connector, as I wiggled it, it would cut in and out.
Wish you luck in figuring out what is wrong with your radio, I'm sure it's driving you nuts.