98 S70 - poor mileage (<24MPG), pinging under acceleration....MAAS? Check Engine indicates "long-term fuel delivery problem.." No fuel leaks, no vacuum leaks -new fuel filter....cleaned MAAS - no change..time to replace?

 

Mass Flow might be bad.

 

Could it be maybe a Knock Sensor..?

 

+1 to Tech.

Also, when was the last tune-up? If the MAF sensor turned out ok, switch fuel grade (unless you're already running 91 or higher), dump a large bottle of Techron fuel system cleaner into a half-full tank and replace ignition components if not done for a while.

Try not to drive the car if it keeps pinging. It can destroy the engine if persisted at certain levels.

The attached are taken from the 850 manual and may not apply to the S70. It may be of some use, however.


JPN

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Trouble-shooting for Long Term Fuel code seems a bit involving and seems to require Volvo scan tool.


JPN

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