Rough running and not enough power on 1999 Volvo V70

My V70 drives rough but the idel is ok, the check engine light is not on. It doesn't overheat. When in PARK I press the gas pedal it makes a rough (grrrrrrr)sound. When driving it makes the rough (grrrrrr) sound and doesn't accelarte as quickly as before from stop or while on the move. I have checked the spark plugs and they are ok. The ignition coil boot had a cut and I replaced it and no change. Can you help?

by in Glendale, CA on May 18, 2010
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3 answers 1 comment
ANSWER by , May 19, 2010
Check the easy things first: -spark plugs -wires -cap and rotor *if DI ignition* -blocked or failing Catalytic Converter (after driving feel the exhaust before and after the cat, as well as the cat itsself. If the cat-back is a major heat difference than in front deem the converter a fail and replace)
COMMENT by , May 25, 2010
One of the ignition coils was bad. I have changed it and have changed the spark plugs. The rough grrr is gone, but I have a different problem now. The engine shuts off after driving for 5 minutes. I guess when it heats up then it shuts off. Any ideas?
ANSWER by , May 25, 2010
Hi, I would check the codes anyway, some may be stored even if the light is off. The fuel pumps can fail on these, I would check the fuel pressure and power to the pump when it is shutting off.
ANSWER by , November 26, 2010
youg might have a bad fuel relay or your fuel pump might have abad seal or air filter might need replaced