I'm kind of lost on this one and have been searching and trying many new things to fix it, but no luck... so hoping someone here will be able to help.

The car starts no problem even after it had sat for weeks at a time. I could start it and restart it multiple times and all good. However I drove it about 40 mins 1 day and it would barely turn over when I went to leave that day. Next day, fires right up. Since then it seemed to get worse. I put in a new alternator even though the old one was charging at 14 volts. New one charges about the same. Charged the battery, would start at first then after running, barely turns over. So seemed maybe it was a starter issue, so put in a new starter, started right up multiple times like before, drove 10 mins, acts like the battery is dead. So thought maybe battery issue despite being a year old... started right up, ran a few mins, acts like it has a dead battery again.

I did clean and check all connections, battery, starter, firewall grommet area etc... all like new. Also battery that acted like it was low, started my 07 ram right up.

The car runs perfect when it starts. Engine was rebuilt, no coolant in the oil or other obvious issues. Exhaust is all new also, including cats.

Anyone ever see one do this before? I did all the obvious things and at this point totally stumped.