Volvo: Volvo 960 3.0 - runs out of puff, vacuum leaks, 1995 volvo 960

Question
Over the weekend I checked the timing belt and it is spot on. There are also no leaks from around the inlet manifold. In my experience it sounds to be a more an electrical problem...is there something I am missing?


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-----Question-----
I have a 1995 Volvo 960 3.0 24v automatic estate. She seems to run fine all the way up to about 80 to 90 m.p.h. when she begins to cough and spit back (missing). I've had the coil packs checked and they have been certified OK. The previous owner has told me that she ran extremely hot some time back and had some work done to rectify it. Any help gratefully recieved. Thanks, Mike.
-----Answer-----
Mike,
Check fuel pressure, make sure the timing belt is lined up and in time. They will run with it being one tooth off on either cam. Change the fuel filter. Add a can of good injector cleaner to help clean any clogged injectors. Change the spark plugs, use Bosch plugs or Volvo ones. Scan and read all codes and see if that will lead somewhere. Check for vacuum leaks around the intake manifold.

Answer
Mike,
An electrical problem yes, you did say that the coils and plug were tested and they are ok. You may want to pull out the injectors and see if there is one that has the end melted sine there was a possible over heating in its's past. Also look carefully at the wire harness maybe it was melted during the overheat. Air mass meters have been a problem, you may want to try a known good one for a test.