Volvo: 90 Volvo 240 Idles fine boggs down when driving, volvo 240 wagon, volvo 240

Question
I have a 90 Volvo 240 Wagon. Car will idle for days,but when you give it gas it shakes/boggs down. Mechanic replaced bad coil wire/dist cap & it ran good for like 5 miles then same thing. he replaced Crank Position Sensor-same thing-any help?

Answer
Jim,
Real hard to say without driving. How is the fuel pressure? Both the main and pre pump work? Could the hose on the pre pump be broken? Is the problem more evenident when the tank is low on fuel? Read the codes in the system let me know what they are.