I have a 1991 940 turbo volvo. I am just stomped on whats the matter with it. I replaced fuel filter,o2 sensor,thermostat,cleaned throttle body, has after market air filter,new battery new alternator new plugs and wires. When its in park it idles rough and is usually on 500 mark on rpm. When in drive it is around 6 maybe 7 but the exhaust signs like it cuts in and out and the car whiling idling is rough like it wants to cut out any ideas.

 

Could be fuel pump issue.
When was the last time the valves where adjusted?

Wait for the experts to get on.

 

well i listened and checked fuel pump and its still pushing fuel and doesnt sound like its not working. The valves were probably never checked but i dont know if people before me did anything with that.

 

I forgot to mention i do have a speedometer bounce every now and again if that helps.

 

and to add to the list lol when it is idling and i open the hood by the turbo theres like a puffing sound like an exhaust leak but i dont feel any air. Turbo still works 100% so still just not sure.

 

could it be a clogged cat

 

Replace all your vacuum lines.

Your base idle should be adjusted to around 700 RPM.