my 88 240 DL with 230,000 miles has developed a problem. It is going through episodes of loss of power where it accelerates very slowly and will not go above 40 MPH , flooring the gas pedal just produces a string of backfires. It has been happening 2-3 times per week, usually on a short around town trips. The car is driven 75-100 miles per week. Weather has been pretty cold since the problem developed single numbers to 20 degrees F. If you shut the car down, and wait two or three minutes, it starts and runs fine. Heres what has been done: new fuel pumps both in tank and secondary,new catalitic converter, tune- up with new plugs,wires, new dist. cap and coil wire,new air and fuel filters, air box thermostat,
throttle body gasket. Still have the problem. I am guessing the fuel pump relay might be going. Is this sensible? any other thoughts?