Hello, I keep getting code 52 on my 1988 Dodge Ram W100 318. I have replaced one fuel injector, cleaned throttle body and replaced gasket, new thermostat, new radiator, new spark plugs, wires cap and rotor, new coolant temperature sensor, new bosch oxygen sensor, new catalytic converter with new air tube, new TPS, new air filter and new fuel filter. All that is left is the one fuel injector which isn't dripping or clogging. It's running perfect. Fuel pressure regulator isn't leaking into the vacuum hose connected to it. The temperature gauge does run on the low side, but the thermostat has been replaced twice and opens right up at 195. Is there a temperature sender that could be causing this? Perhaps a thermostat opening up and never closing? Fuel pump pumping too much? (Never heard of this happening) Also the smog/air pump has been disconnected. So it is attached to the motor along with all of its hoses but the belt used to run it has been taken off because the pump is seized up. The fuel economy keeps getting worse and worse. Any thoughts?

-Billy

 

Have seen the oxygen sensor cause this. Also on mine I had an erratic map sensor do this. I have been fortunate to have a salvage yard that has several d150. If you can locate one in your area it will pay to go picking.

 

 

what brand oxygen sensor did you use? these trucks really don't like the bosch ones. they really like the NTK ones