I have a 1985 240 DL that has a problem with idle. It idle rough after it starts to warm up. As I give it gas on take off it sometimes acts like it wants to miss. Well not exactly a miss but like it is not getting enough gas. Volvo changed the fuels pumps about 18 months at 174k miles, it now has 211k miles on it. Can the fuel fuel be stopped at the present miles? It is getting hard to start in the morning. It turned over about 3-4 times before it will catch. It used to start as soon as I touched the key. Is there a check vale on this car at the fuel pump? It has a new OS, AMM, FPR, new wires, plugs, dist, both temp gauges. The ignition wiring looks ok no bad spots. Coil was replaced about three years ago. New hose from AMM to TB, new air filter. I swapped out the ECU it ran better for a day or two then back to the shaking at idle. What are problems with Hall Sendors when they start to go bad other than a no start? I pulled into the garage a few days my wife told me she smelled plastic burning near the trunk or from under the rear of the car, I also found a humming sound coming from the trunk. I found the ground on the fuel in the trunk was not making a good connection. I retighten it is seems ok now. The noise stopped. Help me solve this problem before my wife tries again to make me get rid of it. I want to keep it but I can't keep pouring money into it.

Thank you,
Ted D