I have a 1988 240 DL that recently refused to rev. It is idling perfectly, but when you give it gas, it sputters and chugs. If you feather the throttle you can get it to rev up, but it doesn't last. When you release the throttle, it goes back to bogging down when you give it gas. Any ideas as to what might be wrong? Thanks!

 

Air leak, bad air mass meter - Some will say try it with the air mass meter unplugged. If it runs better you may have a bad air mass meter.

Make sure basics are in good condition, including the insulation on the engine speed sensor if equipped. You can tell if it has one by looking at the distributor - a car with a speed sensor only has plug and coil wires attached to the distributor. Does that car have the early OBD port for diagnostic codes? (89 might be the first year for a 240) If so have you checked for codes?

https://www.volvoclub.org.uk/faq/EngineOBDCodes.html

 

Bad Mass Air Meter will do this.