90 348TS Check Engine 1-4 and exhaust tip

Hey, we just gota 1990 348 with 40k miles into the dealership and I took it home last night and noticed two issues.

First we had to jump the battery when it came off the truck, so we let it run for 10 minutes before driving it. On my 25 mile drive home the check engine light 1-4 came on and stayed on for about 5 minutes and then turned off for the remainder of the ride.

This morning the car started fine with out a jump, and then about 10 miles into my ride back to work the lite came on, then went off for about 10 minutes, and then is back on now. The car runs just fine, everything seems to be working (although a/c is a little weak, but still cold) the only issue I see if the passenger exhaust tip is rattling, but if I hold it the rattle goes away.

Can those issues be related? Or from what I read online is it just a common glitch for the check engine light?

 

bumppp!

 

How do I pull the codes, it is a 90 so I do not think it has obd 2