94 Mercedes E-420 Codes on engine[b] #6 & #15. [:@] Car starts but will not stay running unless you keep your foot on the gas and keep it at 1500 RPM or better. What do I look for and how can I correct this or these problems. Car has had both Distributer caps replaced and rotors, also new spark plugs installed about 1000 miles ago. roughly 1 month ago. it has been running fine with no problems, until two day's ago. Please help. Big Ben3