I have a 93 fleetwood brougham. I think my engine is going bad but what do i know, my low coolant light comes on and goes off it over heats sometimes i have a acceleration problem sometimes and it looks like oil in overflow tank the oil isn't mixing with the anti-freeze or vise versa there is no smoke coming out of the tailpipe. Please tell me what it is cause ive been told intake manifold, new engine.. I dont what to do!!!!