Volvo: 1988 Volvo 740 GLE B230 eng. auto., volvo 740 gle, fuel pressure regulator

Question
Hi RAY, I have actually 2 questions on my 740. 1st.at idle the engine runs rough and the engine lopes. at higher revs it seems to smooth out. I changed the fuel pressure regulator and that helped somewhat, but it still does it. Any ideas? 2nd when I drive it, the overdrive engages only when it feels like it. I just bought this car and I am not sure of the mileage as the speedometer doesn't work. that the next challenge I guess. any help would be appreciated.     thank you  Pat

Answer
Pat,
The engine lope or miss could also be from the secondary ignition, like cap, rotor, wires, plugs. Also could be a bad or dirty fuel injector.  Might even be a burnt or sticky valve. You may need some tech help to identify what and where the fault is. Some hands on might be required to find the fault. Always not just the easiest things to find.
On the OD is the relay working? Do you have power to the relay and the solenoid on the trans?  Is the fluid level correct? Is the car a stick or Auto? Make the needed electrical tests and you might find the fault(s).