I have a 1996 E300D with 221,000 miles. I recently had radiator, key interlock system, and gear shifter replaced. A week after getting it back from mechanic, car wouldn’t start. Very slow crank and seemed like battery. I took battery off, had it tested, and found out battery was bad. I put a new battery on and same issue. I then took starter off, had it tested, and it too was bad. Replaced starter and now a quicker spin but still not “firing” to start. Any ideas are greatly appreciated.