Ok all, i have a BIG problem, Just purchased my 1986 deville, fully loaded custom made , from its orginal owner, now It broke down in november with a distributer problem, had it fixed and then it ran choppy, it ate that distributer and now i replaced that one , total of 2 distributers i bought

ok so now the car is running choppy like it was before with the bad distributer, also it cuts off after 30 min, just hit 3000 miles which means oil change, but seeing im working on the car, what more should i do? what formula of oil should i replace it with ? 10-W40? any suggestions? cant find the diesel engine oil boby suggested, tried walmart.com , nothing when i searched, please help, I will post diag codes tomorrow.

Will this be overall expensive to fix?
100,000 = new motor
189,000 = current mileage

about to make a one way trip to FL from NYC, will I make it wit the car? drinks 89+ octance , denting my wallet