I have 1993 940 with about 138k miles. This car developed a hunting idle problem some 8k miles ago. I took it to a Volvo mechanic here in Dallas who could not fix it. It is getting worse. Some times the whole engine vibrates, it continues whether under load or in idle. The motor mounts were changed last year and that was when the mechanic tried unsuccessfully to remedy this situation. Has this anything to do with the poor gas mileage that I get? And has it anything to do with poor acceleration too? Every car beats me taking off at a traffic light – even a Pinto. What do I do? I am thinking of changing the Throttle Position Switch and having the injectors cleaned and recalibrated. Any ideas of what to do would be appreciated.