Car trouble/check engine light.

I have a 1994 v6 mustang, mostly stock just a glass pack on the exhaust. A few weeks back the Check engine light came on, it still seems to drive fine but I get no heat anymore, it comes on ocassionally for a minute then goes cold again. I know its not the headgasket, That went a 2k miles ago and I had new ones installed. The cars not overheating. Im also having a non related problem. When I turn my cars wheel all the way to one side and go to pull out of a parking spot or make a sharp turn the wheen seems to hop like its trying to go forward over the wheel almost and makes a weird noise likes somethings loose. I have new struts and ball joints on it, the lug nuts are tight, any idea's what it might be?

Thanks,
jim

Thanks guys, I added coolant, it seems to get heat now, I still have to get the check engine light checked out, the front wheel hop when turning could be needing an alignment, i'll check that out.

Thanks,
Jim

Heat still comes and goes after adding coolant, could the check engine light have anything to do with the heat problem?

Thanks,
Jim