Q: Non Engine Battery on 2006 Mercury Mariner Hybrid

I have had trouble starting my Lincoln. I had it towed to the dealer, and they replaced my battery. Problem still persists. SOMETIMES the car will not start, or turn over. When I get it to, the check engine light comes on. I had my husband take it to the dealer to diagnose the problem, but the dealer says the code doesn't store in the computer. The codes that do come back are gibberish. The last time my husband took it to the dealer with the light on, it stalled. The local dealer said they have no idea what is going on!!! Told me I could pick up my car and the car would be okay!!! But with the non starting, and check engine light coming on, I still feel like there IS a problem.... any ideas?

Engine took several tries before starting. Outside temperature has been 90 degrees for several weeks and I do not use the car often. Is this an indication that the battery in the remote or engine needs to be replaced or do I need to run the engine more frequently?

Car turn over won't start ..alternator.battery.fuel pump rely good so timing belt good to i can hear fuel pump when i start the car but when i turn the key without starting i can't hear the fuel pump. Please help..