'98 v70 2.4l loss of power

Hey! I have a 1998 volvo v70 with a 2.4L engine. For quite a long time, it has had a noticeable loss of power nearly every time I drive it. On occasion, it feels like the the power is normal, -- I think this happens after a few days of relatively low humidity. Also, the gas mileage is nowhere near as good as it used to be. It seems like having the pedal down 1/4 of the way has the same effect as having it down 7/8 of the way. When the pedal is to the floor there is a noticeable throbbing from the engine. When the preformance is poor (as usual) the pedal needs to be to the floor in 2nd gear to accelerate onto a highway. When the power feels normal I can achieve the same acceleration with the pedal about 1/4 of the way down. Spark plugs were replaced 12,000 miles ago along with the plug wires and (I think) the cap and rotor. If I had to guess, I would say a weak distributor coil. Mechanic says its possibly a plugged catalytic converter. Thanks!

Reply to
jciarlan
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Sorry, I forgot to add that this has 140k miles on it. Thanks

Reply to
jciarlan

If there are no codes and the engine is not misfiring then the cat is probably restricted. If that's true, then you need to find out why the engine runs rich all the time, which is what probably killed the cat.

Bob

Reply to
User

I would also err to a plugged exhaust. Sounds like the cat could have broken up and the pieces are moving around sometimes blocking the exhaust.

Tim..

Reply to
Tim..

there are no codes and the engine doesn't misfire, but it does run a tiny bit hot, which is why I suspected a rich mixture. This may be a coincidence but our mechanic cleaned the injectors near the time this happened. Since it runs nicely sometimes I didn't suspect the exhaust. Is there some other way to check the catalytic converter without removing it? Like the compression being abnormally high or something? Also, how would I go about changing the mixture (if possible)?

ps: right around the time this whole thing started happening the check engine light came on with a code PO404 or 440 (I think), meaning that the air pump was malfunctioning. The code was cleared and it was determined to be a computer glitch, though.

Thanks a lot!!

Reply to
jciarlan

An engine running hot for no other apparent reason is also a sign of a plugged exhaust system.

You may be able to remove the o2 sensor for a short time and road test it.

Tim..

Reply to
Tim..

thanks a lot! I will try to remove the o2 sensor. Any ideas on why it would be running rich? thanks

Reply to
jciarlan

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